Good Morning and God Bless those who serve!

I'm a relative rookie at this stuff only owning my Corvette for about two years. However, in that two years I've learned a lot and I hope to pass that to the folks on this forum. I was pretty hesitant to tackle a wiring harness installation; however, it turned out to be a little easier than I anticipated (for the most part).

Below are some hints to hopefully help others. Unless you are completely familiar with the car's history, you can't be sure what has been done over the life of the wiring system. Below are some key things that were done by previous owners.

- Not a single wire was not spliced at some point - no joke. My best guess is that connectors and ends were maintained but the wiring in the middle was replaced. This formed a huge mess under the dash as wires were just stashed away.
- No attention to wiring color codes. As mentioned before, wires were spliced but color codes were disregarded.
- Several additional wires were present but never connected to anything. This included switches that didn't do anything
- Wrong ignition switch - switch present didn't have all the connectors to properly wire to the ignition harness
- Wrong lamp sockets on the tail lamps
- Exposed wiring through the protective plastic insulation
- Ballast resistor wired incorrectly (explains why the previous owner went through 3 coils)
- Headlights grounded to the bezel. Not sure how they worked.
- Horrific splices and burnt wires from previous owners

Now that you can see some of the reasons to rewire, below are some tips to make it go easier.

1) Spend the extra $$ and buy DocRebuild's OoosooEZ diagrams. Between that diagram and the vendor provided diagram figuring out what connector goes where was pretty easy.

2) Before you pull a single connection, survey the entire car looking for things that don't match (lamp sockets, connector, switches, etc...). You want to collect this info before you start to get have the parts ready. Otherwise, you might sit a while waiting for parts and pay multiple shipping costs.

3) Pay specific attention to how the different harnesses are routed between heater vents, wiper cables, body panels... While the AIM shows generally how it goes, it does not provide the necessary detail to get it right the first time. You may have to redo a harness a few times before it clears all moving components

4) Remove the light switch before doing any dash work provides precious space. To remove the light switch, unscrew the bezel, pull the **** out, and while pulling the know, depress a switch located on the bottom of the switch. The **** should come out of the switch allowing you to remove it. Of course, reconnect it last.

5) If you need to remove the ignition switch, turn the key all the way to the left and use a paperclip to insert into the tiny exposed hole. While depressing it, continue to turn key to the left and the tumbler should come out.

6) Make sure you buy the necessary body grommets to protect the harness around the trunk area, departing the firewall, and by the headlight area.

7) On the rear harness, there is pretty good slack and installation is pretty straight forward. In my install, I did have a problem with the lamp assemblies having the incorrect sockets. I didn't want to modify the new harness so I did purchase new assemblies. I personally didn't like the plastic taillight covers since I feel they will bend the wiring at an unacceptable angle and chose not to use them.

There is barely enough wire to extend to the gas sending unit. Try to get this connection on before securing the rear harness.

8) No issues on generator/regulator harness

9) Engine harness had no issues. But be very careful how it is ran. The entrance point by the firewall is pretty busy area with heater vents, and other cables that may rub against the harness if you install it improperly. Make sure you annotate how the other one is ran first.

10) Headlamp bucket. You may need some help on this one due to the horn screw. I tried to re-attach the horn and the screw fell out. First reaction was "Aw ****" but fortunately, the screw is reachable through the fender well. Have a helper hold it in place while you reconnect the horn and ground wire.

Also, make sure that the wiring near the headlight is pushed away from the bezel when you reconnect the actual lamps. This looks like a very easy place to pinch some wires if you rush it.

11) Parking lamp. Removing the old socket from the assembly is a pain but just be patient. New one fits in it great.

12) Dash harness. On the dash harness, try to get the courtesy lamps hooked up first to help position the harness. The courtesy lamps, in my opinion, were extremely tight and very hard to work any slack to help install.

The worst part of the dash harness was re-establishing the ground on the back of the heater/clock plate. There are two wires (in my case I had the heater blower grounded there) and the harness that must connect to the plate. I had to remove the radio to get the space needed and use my wife as well.

The rest of the dash went pretty well. Hardest part was figuring out the routing of the harness.

13) I just remembered that I didn't set polarity but looks like I was spared any problems. However, you might not want to forget this step (see the service manual for the procedure).

14) Tools...tools...tools. Removing the nuts on the dash was pretty difficult just do the working angles and other present wires. May want to have a variety of 3/8" tools to include socket, stubby wrench, and even a brake line tool for weird angles.

15) Double check all connectors and make sure there are no pinched wires. Each wire should have some range of motion if it isn't pinched.

16) Double check all grounding locations (harness grounds and other body grounds). Make sure that are tight, clean, and present a "metal to metal" connection.

17) Take your time and research it. I probably went overboard memorizing the wiring diagram but that is the way I work. If you are in no hurry, just do a few connectors at a time. I think I did rear harness in one day, generator the next day, lamp harness the next, and so forth and so on.

18) If you study the connections, diagram, and take the time to figure out how the system works, it is not intimidating like it first seems.

Hope that helps others out there. Maybe I can finally start "giving back" to the forum.

Jim

 

Yeah, before I replaced my harness, in addition to all the unique fixes/damages you noted, there was a big ball of electrical tape about the size of a tennis ball with a bunch of wiring coming out of it everywhere.

I found with the dash cluster out, installing the dash harness was a breeze.

Doug

 

I was debating to remove the console or not. However, I have some small hands so it didn't present a problem. No doubt it would be easier though.

Jim

 

thanks for the tips. I'll be tackling this job on my 62 some time soon. I got the kit and diagram from lectric industries.

 

Once a complete new harness is installed, is there a procedure recommended for testing/evaluating it to make sure everything is proper before "turning it on"?

 

The one and only one job I won't have to do (fingers crossed) my wiring looks new from front to back and so some PO dealt with it before I got the car.

 

I don't think there is but as I installed each harness, I would check for continuity between specific leads and the associated ground wire. I would also check to verify that there wasn't any wierd resistance in the path.

When it came to turning it on, I had a fire extinguish and my wife ready to push the car out of the garage.. Just the fact of connecting the battery terminals and not having any issues was a victory, I then checked stuff that should work w/o ignition engaged (courtesy lamps), eventually I would engage the ignition where I would have lights, turn signals, etc... Last step was actually starting the car.

I don't think there is any good way to do it but I just went through slowly and cautiously.

Jim

 

I found this older post in a search, and it looks very helpful. Yesterday I started on the complete rewiring of my '58, and began with the rear harness as it seemed the easiest.

Two additional tips I would add to the original post:

- to install the passenger side licence plate light wiring, I removed the rear bumper. Reinstalling it was a pain, particularly lining up the bolt through the side fender without stripping the thread. I thought "there has got to be a better way", so on the driver side I left the bumper on, cut the old light socket off, removed the body grommet, zip-tied the new connector to the old wire and gently eased the new connector through the bumper and hole in the panel, and voila! - the wire was routed with the bumper in-situ.

- feed the harness through from back to front - that way you don't have to pass the rear tail light sockets through the body hole when it already has the antenna and harness itself running through it.