Thursday, February 22, 2018

Reinstalling the Wiring Harness for the Headlights Correctly

As I had mentioned previously in C3 Corvette Low Beams: Inside or Outside?, whoever took the Corvette apart to repaint it, completely screwed up reinstalling the wiring harness for the headlights.

This resulted in not only having the position of low beams swapped with the high beams but also a complete mess with the harness just thrown in behind the nose of the car.

Words that come to mind to describe the mess they made include clutter, chaos, pandemonium, and rat's nest to name a few.

I guess they thought since you can't see it, no one would care. Well, I care and, therefore, had to remove the harness as much as I could in order to reinstall it correctly.



The photos above shows part of the harness (black conduit) attached haphazardly to the nose of the car or just sitting loose on top of the chassis front cross tube, which also doubles as a vacuum tank.

The photo below shows part of the area under the nose of the car, namely the lip that meets the front edge of the hood where the harness should be routed.

As a side note, that ground wire you see (red arrow) should have a clamp to help hold the harness in place. Mine was missing and you can see that someone just tightened the bolt without regard to the wire and that sharp angle has been applying unnecessary pressure to the wire strands, to the point it's about to snap. So I will have to correct all that during reassembly.


After disconnecting the harness, starting from the right side of the car, I carefully took it out in order to inspect and clean it. Because of some of the primer and paint overspray, I am guessing the painter just tucked it into a corner and hoped for the best. That's what you get when you try to get a good deal on a paint job. People will cut corners.

With the loom easily accessible, I cleaned it with brush cleaning solution which removed most of the overspray.



The photo below shows part of the harness where there was no conduit used to protect the wiring, just tape. Since I happened to have some leftover conduit from another project, I took care of that immediately.


The photo below shows one of the factory-installed clips that help secure the harness under the nose lip. But that was the only one present. At least two others were MIA.


This is the same clip shown above, but I installed conduit to help protect the wiring.


Fortunately, I also had thinner leftover wiring loom, so I covered most of the wiring. And I also used electrical tape on the ends of the conduit, along with small cable ties, to ensure everything would stay in place.


Most of the harness and components had overspray, so I spent a few minutes removing as much as I could since it looked old and neglected. As you can see below, one of the two headlamp door opening warning switches (Chevrolet part #3951239 if you need to replace yours), was covered with overspray, and the other one was in similar shape.


And here's the end result after a few minutes with a rag and some paint remover. Quite the difference. Both headlamp door warning switches look as good as new, as do other various connectors. Well, almost as new, as the pins used to secure the switches in place are broken. Instead, I used cable ties.


Since some of the routing clips were missing, I ordered a box of them from Clips and Fasteners. They offer these in different sizes but since I needed only a few for the 3/4" conduit, that's what I ordered. For only $6.99 you get 25 pieces.


Installation is pretty easy. All you have to do is spread the clip so it clamps the conduit. You can secure it in place with tape but I decided against that since this allows you to push or pull the conduit in order to make adjustments.



And here's the wiring loom ready to be reinstalled after cleaning and a few feet of new conduit. I also cleaned all plugs and connectors, as well as the parking and turn light bulb sockets. This is the perfect time to do so.


But before installing the wiring loom back in the car, Chevy diagrams published in the Corvette Assembly Manual, ensure you will route the harness properly.





The photos below show the wiring loom routed correctly. You can see one of the clips in the first photo. Personally, I would have liked more places to clip the harness to, and I'm thinking that next time the hood is off the car, I will drill a few extra holes which will help keep the conduit tucked away securely. But for the time being, this project is done and done right!



With the hood in the way, it is nearly impossible to get good pictures of the area. The photo below shows the small opening between the headlight housing and one of the actuators where you have to route the wiring for the low- and high-beams.

The one shown is the left side actuator (driver's side). The wires go on the left side of the actuator. For the right side, the wires are run on the right side.


And this is how the wiring looks as it enters the headlight housing and plugs into the lamps, with the outermost being the low-beam (3-prong plug) and the inner lamp being the hi-beam lamp (2-prong plug). The third wire (exiting at the top of the photo) is for the headlamp door opening warning switch, which I just tie-wrapped to one of the headlamp brackets in order to keep it out of the way but still somewhat accessible.


And this is how the wiring harness is meant to look from the factory. Actually, you can barely see it, and that's the whole point of this article.


I hope my blog post helps you out if your car's headlight wiring harness has been taken out of the vehicle at some point, then reinstalled incorrectly.

This is not a difficult job and it should not take more than a couple of hours, provided your harness is in good condition. It is also a good idea to use ramps or jack stands for easier access to the area behind the headlamp assemblies from underneath the car.

Thank you for following my '76 Corvette Stingray Blog!

Product Links... (#sponsored)

Klean Strip Brush Cleaner
3/4" Black Wire Loom
• 3/4" Wire Routing Clips
3M Vinyl Electrical Tape
1976 Corvette Service & Overhaul Manual
1976 Corvette Assembly Manual

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