FREQUENTLY ASKED QUESTIONS
and TECHNICAL INFORMATION

Below you will find many of the commonly asked questions our
technical support staff receive on a daily basis.
Use this material as a guideline to diagnose
your vehicle's electrical situation.

See us at Jay Leno's Garage

This information is believed to be accurate and reliable, however, we are not liable for its content.  By using the information herein, you certify that use of the following information is at your own risk and that you accept all responsibility and liability, without limitation, of any occurrence of damage to person or property as a result of using the information.  This information can not be copied or duplicated in any way.
If you see a discrepancy with any information shown, please let us know.

ABOUT OUR PRODUCTS
and things to know before placing an order.

When we hear people telling us that the wiring in their 1950s or 1960s car is still "in great shape", we have to shake our heads and disagree.   We don't make this statement just because we are in the business of selling wiring harnesses.

It comes down to an issue of deterioration.  There is no practical way to completely seal-off the circulation of air and moisture between individual wire strands in a wire.  In addition, most automotive wiring is not protected from hydrocarbon contamination.

The majority of automotive wire is made of copper strands.  Copper  is considered to be an active metal, which means  that it readily reacts with oxygen, moisture, and airborne pollutants.   If you don't believe that cooper is active, leave a nicely polished copper teakettle in your kitchen for a month or two and watch it lose its shine.  The same applies to stranded (automotive grade) copper wire.

Corrosion causes electrical resistance.  Electrical resistance causes heat and other electrical anomalies.

If your wire has become brittle and cracked, it is now in the next stage of deterioration.  It is in immediate need of replacement.  At this stage, a short circuit to ground is eminent.  In a worst case scenario, it can cause a fire.  

Even if you are one of the few lucky enough to even find an  N.O.S. wiring harness, the wire strands will have deteriorated over time just by sitting on a shelf.  For this reason, it would not be wise to purchase an N.O.S. harness.

The same corrosion factor happens to the wire's terminals over time.

Lectric Limited offers wiring harnesses with brand new wire.  Get rid of your car's electrical problems, or potential problems, by replacing all the wiring with new harnesses from Lectric Limited!

Many manufacturers will warranty their products.  But you don't want to have to tear-out your brand new harness because it was not assembled properly, after you've spent hours on installation...not to mention the potential fire hazard.  Why not buy a harness that has been circuit tested before you install it so you only have to install it once?
additional reasons

Our wiring products are sold by most dealers in the automotive restoration market. 

In rare instances, some of the original connectors needed to manufacture a harness may no longer be available to us.  In this case, you would need to use an original connector from your old harness. However, in most cases we will include a functional replacement connector on your new harness.  It will function correctly, and be electrically sound, by may not be correct if you are concerned with having your car judged.

Also, we recommend that before you install your new harness, you compare it with your original harness to insure you ordered the correct harness for your application.

99.99% of our reproduction (not replacement) products will pass the rigorous judging standards of ALL the major Corvette and Chevrolet awards - and be 100% accurate!  That being said, when you if you call us, we would prefer if ask specific questions like, "Are the colors of the wires in your harness exactly as original?" rather than ask, "Will this pass NCRS" or, "The judge took points off.  Is yours correct?"  When it comes to wiring and electrical, we know what was original and what wasn't - It's our business!  People who judge's car shows, perhaps once a year, do make mistakes. :-)

Our strive for perfection, accuracy, and attention to detail has kept us in business for over 30 years.

 www.ncrs.org
 NCRS Top Flight

 www.bloomingtongold.com
 Bloomington Gold Certification

www.chevyvettefest.net
 Gold Spinner Concour
 Triple Crown Award

Whether it be for Chevrolet, Buick, Oldsmobile, Pontiac, Cadillac, GMC, Chrysler, or Jeep, 99% of our reproduction (not replacement) products will pass the rigorous judging standards of ALL the major automotive awards - and be 100% accurate!  

This strive for perfection, accuracy, and attention to detail has kept us in business for over 30 years. 

All of our spark plug wire sets include wire routing instructions.  

All of our "Custom Update Series Wiring Systems" include wiring instructions.  Even scripted on the wires themselves are locations to where that circuit goes to (ex. the wires that go to the headlights would have "headlights" scripted on the wire leads).

A few of our specialized harnesses and kits do include instructions and schematics. These include: 1947-1959 Chevy Truck Complete Wiring Sets, Camaro Console Gauge Conversion Harnesses, GTO Rally Gauge Adapter Harness, Corvette T.I. Ignition Module, all Alternator Conversion Harnesses and a few others.

However, installation instructions, schematics and wiring diagrams are usually not included with our exact reproduction wiring harnesses, nor were they ever included with harnesses once available from dealers or part's store.

We suggest that you have a "Factory Assembly Manual" on hand when installing your new harness. "Factory Assembly Manuals" (if available for your year/make/model) contain general overview schematics, as well as line drawings of how to route the harnesses within your car. The Assembly Manual is what the factory assembly line workers used to properly route the wires - so they reach where they are supposed to. These manuals are available from your local restoration parts supplier.  (Note: A "Service" or "Shop" Manual will usually not provide any information on harness routing).

Another installation tip is to install your new harness at the same time you are removing your old harnesses - one step at a time.

FYI: We do sell laminated wiring diagrams for 53-82 Corvettes and some Chevrolet vehicles that are most beneficial when trying to troubleshoot an electrical problem, but are not much use when installing a harness.

Although most of the N.C.R.S. manuals are very accurate, there are some flaws in these manuals.  Specifically in the areas of battery cable part numbers, scripting on spark plug wire, and spark plug wire boot colors.

So, to answer the question, we are correct! 30 years in the business will attest to this fact. This is our business, not our hobby!

Some of our harnesses require that you ship us a "donor" harness.  We will use one or more components off this donor  harness to manufacture your new harness.

The reason for requiring a donor harness is that some of the unique components required to manufacture a new, reproduction harness, are no longer available, and no longer being reproduced.  Without these essential components, your harness can not be produced. (Of course we use all brand new wire and a majority of new terminals and connectors.)

The needed components, usually connector(s), fuse block or bulk head connector (the bulk head connector is the one that goes through the firewall), must be good condition and not broken.  We will carefully remove the component(s) from the donor harness.  If a connector is used from your donor harness, we will replace the all the terminal(s) with new ones.  If a fuse block is needed, we will replace all the fuse clips and connectors with new ones.

When you place an order for a harness that requires a "donor" harness, we will contact with more specific information, after we receive your order.

Harness purchases that require a "donor" harness include,
(but may not be limited to):
- Buick Full-Size Power Window Harness
- Buick Skylark/Special (1964-67) Dash Harness
- Buick Skylark/Special Power Window Harness
- Chevrolet Chevelle/Monte Carlo/El Camino Power Window Harness
- Chevrolet Corvette (1981-82) Dash Harness
   If you have a 1981-82 Corvette and need a Dash Harness, click here.
- Chevrolet Full-Size (1963) Dash Harness
- Chevrolet Full-Size Power Window Harness
- Oldsmobile Cutlass/F85 (1964-67) Dash Harness
- Oldsmobile Cutlass/F85 Power Window Harness
- Oldsmobile Full-Size (1958) Main Harness
- Pontiac Full-Size (1955-62) Dash Harness
- Pontiac Full-Size (1964-67) Engine Harness
- Pontiac Full-Size (1964-67) Front Light Harness
- Pontiac Full-Size Power Window Harness
- Pontiac GTO/Lemans/Tempest Power Window Harness

These are a "special order" item.  Call us if you have any questions.

Can you explain?

Very few of our are harnesses are refurbished from an original harness; whether it be your original, one you find at a swap meet or junk yard, or one we supply.  These harnesses are un-wrapped, completely inspected, professionally repaired as necessary, completely circuit tested and re-wrapped. They provide customers with a clean, functional, and economical alternative to a brand new harness.

If a harness is refurbished, it will be specified in the catalog listing.  Otherwise all our harnesses are brand new.  Refurbished harnesses include, but are not limited to, 1981-82 Corvette Dash Harnesses.

Refurbished harnesses are a "special order" item.  If you place an order for a harness that requires your original harness, we will contact with more specific information, after we receive your order. Please call us if you have any questions on procedure or availability.

Can your 1981 Corvette Dash Harness be refurbished? See below for more info.

The only way we can determine which dash harness version you have is for you to send it to us for inspection.  At which point, we will need to completely unwrap your harness to see how it was engineered and manufactured.  We can not make this determination over the phone.

If you need your '81 Corvette Dash Harness refurbished AND we determine that you have the version without the design flaw, then yes, we should be able to refurbish it.  If you have the dash harness that has the design flaw, then there is absolutely nothing we can do to make it right; we can not re-engineer it and we will not refurbish it.

However, if your fuse block was of the type made with the black phenolic/bakelite material, these fuse blocks were originally part of the dash harness, and so, we do include them with our dash harness for that vehicle.

All of our Custom Update™ harnesses come with a fuse block.

WHAT DO I NEED TO BUY?

Many times, customers call us to ask, "What is the harness I need to buy that goes from "here" to "there"?"

This chart should help you determine the specific harness, harnesses, or lead wires you might need to either re-wire an entire area of your Corvette (ex. the entire under-hood wiring), or to re-wire a specific component (ex. the starter motor). 

As you will see, some harnesses route to different sections of the car (ex. the dash harness runs from the passenger compartment into the under-hood area; wiring components within both those areas).

Currently, this chart only goes up to 1967 Corvette.  We are working on updating it to include later year Corvettes.

(also see answer below)

First, identify the wiring that goes to the generator/alternator and trace it back.  If the generator/alternator wiring connects to the harness that runs along the firewall (under the windshield), then you will need the Engine Harness. If the alternator wiring connects to the harness that runs along the driver's side fender, then you need the Forward Lamp Harness.

From 1958-62 the charging system wiring of a Corvette was incorporated into the Dash Harness, Engine Harness, and Regulator to Generator Harness.

From 1963-67 the charging system wiring of a Corvette was incorporated into the Engine Harness.

From 1968 & up, the charging system wiring was incorporated into the Forward Lamp Harness.  Keep this in mind when ordering a harness to correct a charging problem.

(also see answer above)

What do I need to buy?

A) T.I. AUXILIARY HARNESS - This is the main wiring that goes from the distributor to the T.I. amplifier box. On 1968-71 Corvettes, this harness mates to the wires coming from the rubber molded connector (or from the rubber molded pigtail) coming from the T.I. Amplifier Box.

This T.I. Auxiliary Harness includes the resistance wire and the conversion kit.  The conversion kit is necessary to convert one of our new engine harnesses to accept this T.I. harness. If your car already has an engine harness that was factory-converted to accept the T.I. harness, and your harness has not been modified or repaired since, then you won't need to use the conversion kit.  The conversion kit can be discarded or saved for possible future use.  (It is up to you, or your mechanic, to determine if your harness has been previously modified or repaired.)

B) T.I. AMPLIFIER BOX EXTENSION - This is the wiring from the internal circuit board that includes the rubber molded T.I. Amplifier Box housing connector -to- the T.I. Auxiliary Harnesses molded rubber connector. Basically, it is the wiring that is part of the amplifier box. This is the weakest link in the T.I. system and must be replaced if you have not already done so. Over the years, the spring-tension on the female terminals of this wiring WILL lose their "grip" on the male terminals they connect to, causing your engine to quit. 

C) T.I. EXTENSION WIRE - Used only on 1968-71 Corvettes, this is the wire that goes from the ignition switch, through the firewall, to the T.I. Auxiliary Harness.

D) T.I. VOLTAGE REGULATOR ADAPTER HARNESS - Used on 1965 Corvettes only, this harness is used to filter-out ignition noise caused from the engine harness.  Without this Adapter Harness, noise induced into the T.I. harness from the Engine Harness could cause your engine to mis-fire.  This harness contains a noise canceling diode. The actual application of this harness is vague.  No documentation is available as to whether it's used on a big block, small block or both.  However, we do sell this harness (# V VR6500A).

E) T.I. CONVERSION KIT - We offer this conversion kit because some dealers do not include this kit as part of the T.I. Auxiliary Harness (We do!).  This kit includes all terminals, connectors & instructions as used by the factory to install T.I.  This kit is not necessary if your 1964-71 Engine Harness and 1964-67 Dash Harness have already been converted to accept T.I. This kit is also not necessary if you purchase a Lectric Limited T.I. Auxiliary Harness directly from us, since we include the conversion kit.

   For your convenience, we are providing copies of our
   T.I. Conversion Kit Instructions Sheets.  Click for:
         1964-65 Corvette (part # VTR6465CK)
         1966-67 Corvette (part # VTR6667CK)
         1968-71 Corvette (part # VTR6871CK)

-------------------------------------------------------

Other T.I. items we carry:
T.I. AMPLIFIER BOX MODULE - This is a solid-state T.I. module that replaces the original circuit board.  It fits completely inside your amplifier box making it undistinguishable from original.  It is a simple screw-in replacement. We offer this module for 1964-71 Corvettes.

Did you know that many times a problem with an original T.I. system can be traced back to the electronic components.  Many years ago, when the T.I. system was developed, Germanium transistors were "state-of-the-art" in electronic technology.  This type of transistor, however, had many limitations and many amplifier failures can be traced back to these transistors.  Our VTR6571AM replacement module uses the newer type Silicone transistors that rarely fail.  Other problems that led to amplifier failure were due to water from a faulty cover seal.  Moisture trapped inside the amplifier box will cause corrosion to the extent it will rust electrical component leads and destroy copper tracks (traces) on the printed circuit board, thus leading to failure.  All of the electronic components in our module is completely encapsulated/sealed.  If water does get trapped inside your box, the module will not be effected.

NOTE: Transistorized ignition is a very specialized performance option that works well, when it works. When it doesn't, it can be very frustrating. From an originality standpoint, if your car was originally equipped with T.I., you would want to retain the T.I. system.

If you are thinking of converting your car from OEM standard (non-electronic) ignition to T.I., don't do it!  Use our Breakerless-SE Electronic Ignition Conversion Kit (#38131) instead.  The Breakerless SE will be a cheaper, much easier to install, much more reliable, and better alternative to T.I.

Our recommendation on internally regulated alternators is to use a genuine Delco SI or CS type for all applications.

Lectric Limited offers an easy and inexpensive solution if you want to convert your wiring from an externally regulated alternator to an SI or CS type, internally regulated alternator.  Order our Alternator Conversion Harness.  View our On-Line Catalog & Order Form to see if this harness is available for your vehicle.

F.A.Q. on Internally Regulated Alternators:
The most common alternator ever produced is the 10SI ("SYSTEM INTEGRATED"), with the 12SI being an upgraded version by means of better cooling (noted by a plastic fan) to handle higher current outputs. The 15SI and 17SI are physically larger units.

Delco 10SI Series , 61 Amp, 12 Volt, CW, 1-Groove Pulley
Used On:  (1985-73) Buick, Cadillac, Chevrolet, GMC, Olds., Pontiac 4, 6, 8 Cyl. Replaces: Delco 1105360

Delco 12SI Series , 78 Amp, 12 Volt, CW, 1-Groove Pulley
Used On: 1989-83 Buick, Cadillac, Chevrolet, GMC, Olds., Pontiac 4, 6, 8 Cyl. Replaces: Delco 1100250, 1105370, 1105372 & others

Delco 12SI Series, 94 Amp, 12 Volt, CW, 1-Groove Pulley
Used On: (1987-84) Buick, Cadillac, Chevrolet, GMC, Olds., Pontiac 4, 6, 8 Cyl. Replaces: Delco 1101308

The latest series of alternators to be introduced is the CS ("CHARGING SYSTEM") 130 or 144 (for 130mm or 144mm stator).

Delco CS130 Series, 100-105 Amp, 12 Volt, CW, 1-Groove Pulley
Used On:
(1990-88) Buick Estate Wagon 5.0L
(1990-88) Cadillac Fleetwood Brougham (RWD) 5.0L
(1990-88) Chevrolet Caprice 5.0L
(1990-88) Oldsmobile Custom Cruiser 5.0L
(1989-88) Pontiac Safari Wagon 5.0L
Replaces: Delco 1101229, 1101275, 1101292

Delco CS144 Series, 140 Amp, 12 Volt, CW, 6-Groove Pulley
Used On:
(1996-94) Buick Roadmaster 5.7L
(1996-93) Cadillac Fleetwood Brougham (RWD) 5.7L
(1996-93) Chevrolet Caprice 4.3L, 5.7L
(1996-95) Chevrolet Impala 5.7L
(1995-92) Chevrolet Lumina APV Van 3.8L
(1995-92) Oldsmobile Silhouette 3.8L
(1995-92) Pontiac Trans Sport 3.8L
Replaces: Delco 10479891, 10480201

Which is correct?

However, if a fiberglass headlight bucket got damaged and needed replacing, the only available option was a replacement headlight bucket made of metal.  And through the years, many of the original 1963 Corvette fiberglass headlight buckets were replaced with the metal ones.  Consequently, the wiring had to be changed.

We offer a VHX6367 Headlight Bucket Extension Harness for those 1963 Corvettes that have the newer, metal buckets.

If you are not sure if you have a fiberglass or metal headlight bucket, put a magnet to it!

Our 1956-58  7" Bulb Set (part# SB5657S) will fit, and be correct for, all 1956-58 GM cars & trucks with a 2 headlight bulb system. Complete set includes (2) hi-lo beam bulbs.

Our 1958-59  5-3/4" Bulb Set (part# SB5859S) will fit, and be correct for, all 1958-59 GM cars & trucks with a 4 headlight bulb system. Complete set includes (2) hi-lo beam bulbs and (2) hi-beam bulbs.

Our 1959-69  7" Bulb Set (part# SB6169S) will fit, and be correct for, all 1959-69 GM cars & trucks with a 2 headlight bulb system. Complete set includes (2) hi-lo beam bulbs.

Our 1960-67  5-3/4" Bulb Set (part# SB6067S) will fit, and be correct for, all 1960-67 GM cars & trucks with a 4 headlight bulb system.  Complete set includes (2) hi-lo  beam bulbs and (2) hi-beam bulbs.

Our 1968-71  5-3/4" Bulb Set (part# SB6871S) will fit, and be correct for, all 1968-71 GM cars & trucks with a 4 headlight bulb system.  Complete set includes (2) hi-lo beam bulbs and (2) hi-beam bulbs. Also see note below.

NOTE: Our 7" Bulb Set (part # SB6169S) will also fit 1970-71 GM cars & trucks with a 2 headlight bulb system, but may not be 100% correct as far as show judging is concerned. However, they will be substantially closer to original than bulbs found at an auto part's store.

Download a free T3 Headlight Bulb Chart (.pdf format)

What is entailed?

But getting back to the question...All original "point type" distributors require no more than 9.6 volts (approximately) to operate correctly. Most GM cars use a "white cloth covered" resistance wire or a "ballast resistor" to reduce the line voltage to the coil from 13.7 volts (approximately, when vehicle is running) to the necessary 9.6 volts (approximately). The "white cloth covered" resistance wire or a lead from a "ballast resistor" must not be used to power a GM H.E.I. distributor. This is a common mistake, that will degrade the performance of the ignition system.

All GM H.E.I. distributors require full system voltage of 13.7 volts (approximately, when vehicle is running) to operate properly.

We can build you an original style harness already set-up for H.E.I.  Simply indicate "H.E.I. Conversion" when ordering your engine harness.

What is involved?

1967-69 Camaros:
The preferred and easiest method of converting a Camaro from warning lights to gauges, is to replace the Dash Harness, Forward Lamp Harness, Engine Harness and the Console Harness with harnesses manufactured for cars with gauges, that we offer. View our On-Line Catalog & Order Form.

1970-up Camaros:
You would need to buy and replace your Dash Harness, Instrument Cluster Harness (if applicable), Engine Harness (if applicable) and a Forward Lamp Harness (if applicable).

1970-72 Chevelle / El Camino:
All 1970-72 Chevelles require replacement of the Dash Harness to a gauge style harness. 1970-71 models also require replacement of the Forward Lamp Harness to a gauge style. In addition, 1972 models require replacement of the Engine Harness to a harness manufactured for cars with gauges, that we offer. View our On-Line Catalog & Order Form.

QUESTIONS BEFORE INSTALLATION

Keep in mind that all Lectric Limited harnesses are built using the most current General Motors blueprint revisions.  (What this means is that, for example, in 1968 there may have been three revisions to the dash harness - revisions that were sometimes made after the prior versions were already installed in cars.).  Lectric Limited uses the most current blueprint revisions to assure that your new harness has the most current function and safety revisions integrated into the harness.

Occasionally, there may be instances when you may notice slight differences from your original harnesses. (These differences normally do not affect fit or function.).

What happens many times is that a car may have had a "service replacement" harness installed.  Although these service replacement harnesses were manufactured for dealers and installed by dealer's mechanics, they were not exactly manufactured like the original harness for that car.  These service replacement harnesses, in many instances, serviced many type of cars.

It is not uncommon, in fact it is very probable, that this is the case. Most schematics or wiring diagrams, including those found in the assembly manuals, are not 100% correct or up-to-date (and they usually reflect the wiring for a baseline car with no options).

Schematics usually don't reflect wiring changes, revisions, or additions due to optional equipment such as: gauges, consoles, automatic transmissions, big block engines etc. Unfortunately, GM never produced schematics for cars equipped with these options.

Although most of the GM wiring diagrams are correct, and can be a valuable tool when troubleshooting an electrical problem, they do contain flaws; flaws in wire color, wire gauge, connector cavity, graphics, etc.  This is usually because they do not reflect running production line changes (a change that may have been made on the production line but was not later corrected on the original wiring diagram), or later revisions.

All our wiring harnesses are the most current and certainly correct. But we reproduce our wiring diagrams exactly as GM published them.

Keep in mind that a wiring diagram is very helpful when trying to troubleshoot electrical problems, and should be used as such.  But please do not use it as the "standard" by which you think a harness should be made.

Believe it or not the fuse blocks were not always screened properly, and as many of you are aware, service manuals are not always correct either.  We have done the research.  We know.

When mated with the bulkhead connector mounted on the firewall, this tar/grease prevents corrosion from forming on your terminals, and acts as a vapor and moisture barrier.  Do not remove this grease or allow the grease to come in contact with your clothing. It will stain.

HELP WITH INSTALLATION

If you decide to first completely remove your harness, you may want to do the following: When removing your old harness from the car, remember to mark where the original wires were connected and/or take reference photos. We also suggest that you have a "Factory Assembly Manual", if available for your year/make/model. (Note: A "Service" or "Shop" Manual will usually not provide any information on harness routing).  The Factory Assembly Manual contains general overview schematics, as well as line drawings of how to route the harnesses within your car. This manual is what the factory assembly line workers used to properly route the wires. They are available from your local restoration parts supplier and will simplify the installation of your new harness.

If you have any questions regarding "what goes where" on your Lectric Limited harness, call our technical support line for installation tips.

Note that some of our Engine and Forward Lamp harnesses utilize a special di-electric grease as original.  This grease is smothered inside the bulkhead connector that mounts to the firewall.  Do NOT remove this grease; it is a corrosion inhibitor.  Do not allow this grease to come in contact with your clothing.  It will stain.

Every Lectric Limited wiring harness has a white assembler's tag on it.  This identifies the harness to us for tracking and troubleshooting should there be a problem.  We recommend that you leave this tag on.  However, if you want to remove it please Do NOT remove this tag until the harness is installed and working properly.

The other wire, if applicable, with the same size ring terminal as the Purple wire, goes to the "R" (run) or "C" (coil) terminal on the starter solenoid.  This wire color can be Yellow,  Pink,  Green, Black w/Pink stripe, or Black w/Yellow stripe.

The wire with the large ring terminal goes to the "B" (battery) terminal  post (large post) on the starter solenoid. This connection may contain 1 or more wires, usually a heavy 10 to 12 gauge wire or fuse link wire. These wires could be Black, Red, Red & Black, or Fuse Link in the following colors: red, orange, brown or black.

The Black wire, usually 14-16 ga., and usually breaking out of the harness 6 to 10 inches before the wires listed above, goes to the starter motor mounting bolt or bell housing bolt (ground).

These lamp sockets were designed with 2 flat sides.  Get a 7/16" open-ended wrench and slide it into the flat sides of the socket. Use a twisting motion to pop-out the socket.

Do not pull the socket straight out!  Doing so may separate the metal retainer from the plastic socket, and the socket will be ruined.

As a reference, we recommend that you purchase a Factory Assembly Manual (not a Shop or Service Manual).  The Assembly Manual is what the factory assembly line workers used to properly route the wires - so they reach where they are supposed to. However, on rare occasions, we've found that the Assembly Manual is NOT always correct. (go figure).  So please keep this in mind.  If an assembly manual is not available for your vehicle, then you would need to look at an original car for wire routing information.

On other occasions, purchasing an aftermarket product can lead to the problem. For example, if you use an original Horn in your 1963-67 Corvette, your new wiring harness will reach the second horn and work perfectly.  If you use an aftermarket or incorrect replacement horn, the terminals on that horn were not placed in the original location.  And in this case, the wires leading to the horn will not reach if routed as original.

As we state throughout our website, we manufacture all of our wiring harnesses to the original blueprint specifications. So they're correct! In the above situation, you would either need to purchase an original horn, make the wiring modification yourself, or determine a way to make the wires reach.

IT'S NOT WORKING (GENERAL PROBLEMS)

Do not use Teflon tape, pipe dope, or any other material on the threads of your sending unit!!!  Screw the sending unit right into the engine.

Any material between the threads of the sending unit and the car's ground (engine) can result in your gauge working improperly, or not working at all.  Without the sending unit being grounded, your temperature gauge will show an approximate 100 degree reading (pegged to the left, cold side, of the gauge) no matter what the engine's temperature.  If your sending gauge is making a poor (high-resistance) ground to the engine because of Teflon tape or pipe thread compound, your gauge will read cooler than the actual engine temperature.

Also, you should never over-torque the nuts on the back of your temperature gauge.  A very fine winding wire is attached to the back of those nuts.  Over-torquing the nuts will tear this fine wire from the inside of your gauge.  This is a VERY COMMON mishap.  This will cause the gauge to either not display or possibly jump up & down as you are driving (because the gauge wire is making & breaking electrical contact).

Did you know Lectric Limited offers accurate replacement Temperature Sending Units that will perform as-original?  These sending units will make your temperature gauge read accurately (provided you have resolved the possible problems shown above).

Most likely you, or a previous owner, had installed a generic sending unit.  Auto supply stores carry generic sending units that will fit and function in your engine,.  But because these sending units cover a broad range of years/makes/models, they do not have the same precision resistance rating as the factory sending unit specifically designed for your year/make/model car.

These generic replacement sending units may either work, or may give inaccurate readings. It would now be up to you to determine if your gauge displays an accurate reading.

We can solve your first problem.  Lectric Limited offers accurate replacement Temperature Sending Units that will perform as-original.  These sending units will
make your temperature gauge read accurately (provided you have resolved the following problems).

The 2nd possible problem:
If your temperature gauge originally had a resistor bridging the silver post (ground) and the copper post directly across, this resistor may be missing.  This is typically a 90 ohm ceramic resistor and must be used.

Below is a diagram of how a typical temperature gauge should be wired.

If the value of the resistor, on the back of the gauge, bridging the silver post and the copper post directly across, is too high, your gauge will read hotter than the engine's actual temperature.  With no resistor (high resistance state) your gauge will peg to the right.  (Note: The correlation between resistance and the gauge display is exactly the opposite when adding more resistance in series with the sending unit. If you add more resistance in series with the sending unit, your gauge will display cooler than the engine's actual temperature.)

If the value of that resistor on the back of the gauge is too low, your gauge will read cooler than the engine's actual temperature.  With shorted terminals (no resistance state) your gauge will peg to the left. (Note: The correlation between resistance of the sending unit and the gauge display is exactly the opposite.  If you could subtract the resistance of the sending unit, your gauge will display hotter than the engine's actual temperature.)

The 3rd possible problem:
You do not have your gauge wired properly.  Below is how a typical temperature gauge, with 4 terminals, should be wired.  Also shown are 2 ways that you can "fool" your gauge to display/read cooler.  Although we recommend using the correct temperature sending unit, adding an external resistor is an option.

WARNING!!! Jury rigging your car's temperature reporting system to force it to read "accurately" under normal conditions without first understanding which component(s) of the system are off can be very dangerous. For example, if you "fix" a temperature gauge with a 50 ohm resistor, when in fact the gauge was operating correctly, could result in your gauge displaying an acceptable 190 degrees (normal driving temp.) when your car is actually operating at a dangerous 260 degrees.  Use your discretion. 

The 4th possible problem:
Sometimes, in order to correct an inaccurate gauge reading, previous car owners have been known to install a resistor in series with their temperature gauge.  Unknown to you, you may have a hidden resistor somewhere between your temperature sending unit and gauge. Additional resistance will cause your gauge to display/read cooler than the actual engine temperature.  This resistor needs to be removed in order to give you an accurate gauge reading with our new, accurate sending units.

The 5th possible problem:
Did you use Teflon tape or pipe compound on the threads of your sending unit?  If you did, you're not supposed to. Do not use Teflon tape, pipe thread compound, or any other material on the threads of your sending unit!!!  Screw the sending unit right into the engine.

Any material between the threads of the sending unit and the car's ground (engine) can result in your gauge working improperly, or not working at all.  Without the sending unit being grounded, your temperature gauge will show an approximate 100 degree reading (pegged to the left, cold side, of the gauge) no matter what the engine's temperature.  If your sending gauge is making a poor (high-resistance) ground to the engine because of Teflon tape or pipe thread compound, your gauge will display/read cooler than the actual engine temperature.

The gauge displayed a reading that was higher than the actual engine temperature.  Consequently, your car may be within standard operating temperature even though your gauge reads hot.  Click Here for the actual Technical Service Bulletin (TSB), issued by Chevrolet in November 1965, addressing this flaw.

The internals of the 1963, '64 & '65 temperature gauge were electrically the same.

The '63 was cosmetically similar to the '64, but much different than the '66 gauge.  Therefore, replacing a '63 or '64 gauge with a '66 gauge was unacceptable for many owners.  However, since the '65 gauge was cosmetically similar to the '66 gauge, the '66 gauge (that functioned properly) was a suitable replacement for the '65 gauge.

We can only assume that this is the reason the TSB does not specifically address the 1963-64 Corvette gauges, even though the gauge flaw applied to those years.

Please note that our replacement temperature sending unit will not correct this factory flaw.  To correct the flaw in 1963-66 Corvette gauges, you may need to install a 270 - 330 ohm, 1/4 watt ceramic resistor across the 2 posts. This should supply your gauge with the correct resistance in order to read more accurately.

A resistor may be added to make your 1963-82 (approx.) gauge read cooler, and closer to the actual engine temperature (thus compensating for the gauge flaw).  There are 2 options shown:

OPTION #1:  Using 330 ohms as a base line (meaning to start with a 330 ohm resistor), the more you decrease the resistance, say from 330 to 270 ohms, the cooler the gauge will display.  In effect a 270 ohm resistor will make your gauge read slightly cooler than by using a 330 ohm resistor - with the resistor placed between the 2 posts as shown in the diagram above.   We do not have specifications correlating ohms to temperature.  You will just have to try different value resistors until your gauge displays the actual engine temperature. CAUTION: Do not install too low a value resistor, or you may short-circuit the posts.  NOTE: Do not confuse the resistor of this value and in this location (between the 2 posts on the gauge itself) with the resistor mentioned in Option #2 (below).

OPTION #2:  On any gauge, you can add a resistor at some point between your temperature sending unit and your gauge.  The higher the resistor value, the cooler your gauge will display.  We do not have specifications correlating ohms to temperature.  You will just have to try different value resistors until your gauge displays the actual engine temperature.  A suggestion is to start with a 5 or 10 ohm resistor.  Keep adding resistance until you get the desired gauge reading.

2.) If you install one of our VTR6571AM modules and are having problems with your T.I. system not functioning, 99.999% of the time the problem lies in the female terminals in the Amplifier Box Extension wiring.  This wiring connects the module to your wiring harness.  This is the weakest link in your T.I. system.

Over the years, the spring-tension on these female terminals WILL loose their "grip" on the male terminals they connect to. A voltage drop of only a 1/2 volt will cause your module to fail. It is IMPERATIVE that the Amplifier Box Extension wiring be replaced when installing a new T.I. Box Module.  Don't fool yourself into thinking "My old wiring looks good.  It'll be fine".  It won't be!

We offer two different T.I. Amplifier Box Extensions. The Lectric Limited part #VTR6468BXT is for 1964 to early 1968 Corvettes, 1966 Chevy II/Nova, 1964-66 Tempest/Le Mans GTO, 1964-66 Pontiac Full-Size. Part #VTR6871BXT is for 1968 (2nd design) thru 1971 Corvettes and 1969 Camaros.

Numerous studies have determined that there's nothing you can do about this problem with the existing, original wiring. Even by adding additional grounds, this problem will not be corrected. It's a GM design flaw you'll just have to live with. :-)

All of the above are critical in the correct operation of the flashing circuit.

A note about bulbs...you can NOT interchange 2 contact bulbs for single contact bulbs.  They may physically fit but will either not work properly or blow a fuse.

For some cars, we offer complete fuse & flasher kits with all the properly rated fuses and lamp flashers.  See our On-Line Catalog & Order Form for your application.

What do I do?

Many times critical ground wires are left off when doing a restoration.  Or, the underside of the terminals that ground the chassis, engine, etc., are corroded or not securely fastened.  If corrosion is the problem, it might not be apparent until the terminal is removed and examined.

Make SURE that the chassis, engine, and any other place that must be grounded has a good solid ground to the negative side (ground) of the battery.

The old saying still holds true..."Check your grounds!"

Note: We sell ground strap sets for many applications.
See our On-Line Catalog & Order Form for your application.

It has been our experience that when a customer has burned-up their harness, and they check the continuity of the terminals posts on their horn relay, voltage regulator, and/or generator/alternator, they find that at least one is shorted to ground.   A harness that's shorted-to-ground will take only seconds to burn.

It may be that the "rebuilt" horn relays currently being sold are, for the most part, only