Rewiring 1957 Corvette

[Theodore K.]

I just received all new wiring harnesses for my 1957 which still had original wiring. These were from Lectric Limited and was the deluxe wiring set. It came in several sections for various portions of the car. Does anyone having done this have a recommendtion as to which sectionto do first? Any help would be appreciated to minimize errors.
Ted von Kampen

[Dan D.]

Re: Rewiring 1957 Corvette

Ted,

I have replaced all the harnesses in my 57 using Lectric Limited harnesses. I have found the replacement harnesses to be very accurate. I don't think it makes much difference which one you do first. The rear harness is much removed from the other harnesses and you could probably do that one at any time. The lamp forward harness is by far the most complex as it has most of the under dash wires. You should probably replace that one as soon as you remove the old one so as to not forget how it goes. Take photo's of everything you can. That helps immensely when re-assembling.

I'm an electrical kind of guy, so wires don't bother me much. I just took everything off and didn't replace anything for several months while the rest of the car was being worked on. But if you do one at a time, you should be able to figure it out okay. If you do stumble on something there are enough guys here to bail you out. -Dan-

[Mike M.]

Re: Rewiring 1957 Corvette

be sure the firewall cardboard/jute insulation is installed before installing the harness. when i re-wired both my 57's and my 56, i used the original plastic connectors(yellowish in color) after removing the black lectric limited connectors. judges will check for color of connectors. mike

[Theodore K.]

Re: Rewiring 1957 Corvette

Dan,
Thanks for reply. The photos are a good idea. I used that on various engine projects. Saved my bacon once on that. My problem and the reason I am replacing them (besides the age) was my headlights keep cutting out at the most in-opportune time. About piled it up last summer on one of those times. I replaced headlight switch, dimmer switch, connectors etc. I keep thinking there is a short in the wiringup front but cannot find it as it only happens occasionally. I am an electrical engineer so that doesn't bother me either, but I have found the various guys on here to be most helpful. . If I hit a roadblock I will most certainly hit you all up for help.

[Theodore K.]

Re: Rewiring 1957 Corvette

Mike,
Thanks for the advice. I am not changing the firewall insulation so that should be okay. Good advice on the connectors. I will not be having this car judged so I think I will stick with the new ones as the old connectors seem brittle.

[Bruce B.]

Re: Rewiring 1957 Corvette

One thing I do is to lay out each harness and compare it to the new one.
Sometimes subtle differences in configuration and wire length can cause problems.
I also found that on my early 57 the original temperature wire was orange, not blue as supplied, the supplier changed it at no charge.
Typically the job is pretty easy.
One word of caution, the GM wiring diagram shows the amp meter wired incorrectly. Hooking it up per the diagram will not hurt anything but will show discharge. Reversing the wires will correct the situation.
Good luck.
Bruce B

[Dan D.]

Re: Rewiring 1957 Corvette

You don't have Halogen headlights, do you? Other threads on this forum have indicated that the additional current the Halogens draw is enough to trigger the circuit breaker built into the headlight switch. I have a hard time believing the harness will intermittent your headlights. -Dan-

[Jerry B.]

Re: Rewiring 1957 Corvette

Another hint. Attach some type string on thr old rear harness and antenna before you pull it through. It will be a lot easier to pull back the replacement. I would have been grateful if i knew about this tip before i removed mine. Now, i was told i would have to drill holes in the floor. I don't think so.

[Dan D.]

Re: Rewiring 1957 Corvette

Jerry, you should be able to use an electricians fish line to pull the wires through. I fed the fish line (with a string attached) through from the gas tank area forward through the rocker panel and found it in the grommet hole back of the kick panel. Used a wire with a hook to pull the string up through the grommet hole, attached the harness to it, and pulled it all back. I would not drill any holes in fiberglass.

Not to jump this thread, but are there separate holes and grommets for the antenna wire, or does it go through the grommet with the harness wires? -Dan-

[Paul J.]

Re: Rewiring 1957 Corvette

Ted, there are two techniques that I've used. One is to lay the new harness loosely across the area that you're working and switch each connection that you come to with the new harness. You have to be cognizant of any specific routing that requires you to remove a lot of the original harness and several connections at a time (like going through holes). That's where pictures and notes can be a big help. The other way is to remove all of the harness, which gives you the opportunity to study it more easily and compare the two, as Bruce suggests. This is the only method that I use now since I'm trying to only do frame off restorations. As for there being any sequence, if you have'nt done this before do the easiest one first to learn the tricks and build your confidence, although with your background I doubt that you'll have any trouble.

Paul

[Theodore K.]

Re: Rewiring 1957 Corvette

Dan, I do not have Halogen headlights. Just the normal OEM type. I have tested the new replacement switch on a test bench, loading to over 15amps and the switch does not open nor does the breaker contacts get warm. The way it happens is just all of a sudden. when they come back on they tend to stay on for awhile. Very strange.

[Dan D.]

Re: Rewiring 1957 Corvette

Dan, I do not have Halogen headlights. Just the normal OEM type. I have tested the new replacement switch on a test bench, loading to over 15amps and the switch does not open nor does the breaker contacts get warm. The way it happens is just all of a sudden. when they come back on they tend to stay on for awhile. Very strange.

Hi Ted,
Does this mean you have the new harnesses installed and they are still cutting out? If so and the breaker checks out okay, then I would try this trick. But first, a couple of questions;
1. I assume it is both low beams and high beams. If so, then the problem is probably not near the headlights themselves.
2. How about the high beam indicator in the dash. Is that out too?
3. How about the taillights?
4. If the breaker is interrupting because of excess current, then it will reset quite quickly, as there is not much mass in the breaker arm and it will cool off quite rapidly.
5. You may not be chasing a short - may be an open. You can try this: Hard wire a voltmeter (or 12V dash light bulb) to the red wire supplying power to the headlight switch. Hang the bulb inside the cab, and see if that remains on line when the lights go out. Assuming that it stays on, then advance the wire to the breaker input, then the breaker output, etc. until you loose power to the bulb. Sounds like this could be a time consuming effort, but it will pinpoint the problem for you in due process of time. To save time and near disasters, wire several bulbs up so you get an answer the first time they go out.

Good Luck,
-Dan-

[Theodore K.]

Re: Rewiring 1957 Corvette

Dan, I wrote a reply but it disappeared. To answer you questions.
1. I have not yet installed the new harness. The car has been in winter storage. I have the harnesses and will start the process soon.
2. It is both high and low beams. I don't recall if the indicator is on but I kinda think it still switches with the dimmer switch (also has been replaced)
3. Tail lights stay on as do the dash lights.
4. The lights come back on in 1-2 minutes. They go off quicker if the high beams are on. So drive on low beams when this happens.
5. I have thought of an open also. Thanks for your trouble shooting procedure. I have also thought about doing that. If the new harness doesn't cure the problem then I will try that.
thanks,
Ted