Thursday, February 8, 2018

C3 Corvette Low Beams: Inside or Outside?

The photo below shows how the previous owner had the low beams installed, and as far as I know, none of the other five C3 Corvettes I owned in the past looked like this. Besides, it looks stupid to me so I had to do something, even though it took me three years to get around to it.

But this is not just a matter of unplugging them and then plugging them in the correct position. Nope. It takes a bit more work than that.

Since I rarely drive my Vette at night, this project kept getting pushed to the back burner, but since I recently refurbished the headlight actuators, I felt it was time to get this issue taken care of.

I started by manually opening the headlight assemblies, and then I removed the headlamp bezels. This time I did not use the RhinoRamps thinking this was going to be an easy and quick job. I was wrong!

The headlight bezels are secured by four screws as indicated by the arrows below. Be careful when removing them as the machine screws are tiny and you don't want to lose one of them.

This also is an excellent opportunity to inspect the screws and clean or replace them as necessary. There are a total of four per bezel: two small machine screws and two sheet metal screws. The last ones are pretty common automotive-type sheet metal screws, but make sure they have the built-in sleeves.

Also, note the countersunk heads, so make sure you use the correct hardware if you need to replace yours.

In my case, they were in decent condition so I simply cleaned them with a small steel brush to remove any surface corrosion. A light coat of WD40 does not hurt, either.

This is also an excellent opportunity to clean and polish the bezels which, by the way, should match the color of the body.

Next were the polished headlamp bezels or rings, which have three tabs each and are secured to the headlamp assemblies by small sheet metal screws.

Note the red arrows below that point to the bezel screws. The ones next to them (one at the top and another to one of the sides) are used to adjust the headlights. Leave those alone and just remove the ones that are connected to the ring tabs.

These screws tend to rust and weld themselves to the anchor tabs on both the rings as well as the housings so you may need to spray PB Blaster or some sort of penetrating fluid to loosen them up.

Once the screws come out, you can remove the ring and lamp. By the way, using a towel to protect the paint may not be a bad idea.

The lamp rings are stainless steel, so they clean up and polish nicely, and this is the perfect time to take care of them. They are hardly noticeable since they're covered by the headlight bezels, but that's no reason not to—at least—clean them.

This is a side-by-side comparison of a dirty lamp ring versus one that's been polished. And I also straightened the ring tabs with a pair of pliers.

Did I need to polish the inside of the rings? Of course not, but I did, anyway. The photo below is another comparo of cleaned and polished versus a dirty lamp ring. I like mine to be as clean as possible.

Back to the headlight assemblies...

The red arrows below point to the headlight adjustment screws. The top screw adjusts vertical movement while the one on the side is for side-to-side adjustments. I will probably need to adjust mine at some point, but that's another article. Needless to say, there are plenty of instructions online on how to adjust headlights.

Since the lamp ring screws were covered by a good layer of surface rust, I cleaned them the best I could with a small steel brush. That helped remove most of the surface corrosion, but they still looked pretty ratty so I had to do something not just for looks but also for longevity.

I brushed Loctite Naval Jelly Rust Dissolver and allowed them to dry for a while before I reinstalled them.

You can order this product online or buy it at most auto parts stores. It's easy to use and it works great.

Headlamp housings are secured in place by a spring in addition to the adjustment screws. Those are slotted near the head and the housing tabs slide into those slots which helps anchor the whole assembly securely.

The photos below show how the springs are secured to the housings, and believe it or not, they are under quite a bit of tension so you must be careful to remove them safely.

There are other approaches, like using a metal hook, but I like to use locking pliers to grab the end of the spring, then carefully pull the spring in order to release it from the retaining cup. I use the same technique to secure the housing back in place and it works very well.

By the way, these springs are connected to the assembly so they will remain in place.

Again, using a rag or towel to protect your paint as you use tools near the headlight openings is advisable. Especially if you use locking pliers to disconnect and reconnect the tension springs.

And this is how the headlight assembly looks like when you remove all of the items mentioned above. At this point, it was hard for me to resist the temptation to remove the whole assembly off of the car in order to restore it, but that's a project for some other time.

At this point, I thought all I had left to do was to swap the lamps and connectors around.


This "easy" project was about to get a bit more complicated than originally planned.

At the time I was not aware that the lamp housings have small differences between them, and those differences affect how the lamps fit (or don't fit) inside them.

The lamps have tabs (see photo below) that should align with corresponding recesses on the housings so the lamps sit flush. Well, there was no way these things were going to allow that, no matter how hard I tried. So I reassembled the passenger side headlight assembly, since I was working on that one, and went in the house to think about how to solve this dilemma.

After about an hour it occurred to me that maybe the guys who repainted the car for the previous owner had swapped the housings when they put the car back together. So I went back in the garage and took both assemblies apart (again) to test my theory.

So what happened?

I was right!

They not only swapped the headlamp housings, but they also routed the headlight wiring harness wrong, which is something I will add to my "To Do" list.

I also took out the factory Assembly Instruction Manual (AIM) to confirm my findings, and it proved me correct.

As the diagram below shows, the low-beam connector is a 3-prong unit, while the high-beam uses a 2-prong connector. The connectors in my car were installed in the wrong location. The diagram also shows the correct routing for the wiring harness. Mine looks nothing like that.

So, after cleaning and detailing all the hardware of the driver's side assembly, I swapped the housings from one side to the other making sure everything fit as intended by Chevrolet engineers.

I also had to re-route the wiring harness in order to connect the lights in the correct order and position.

This task proved to be a bit of a pain since they really routed the harness wrong which did not leave me room for error.

I then tested headlight operation manually to ensure there were no conflicts and the assemblies opened and closed freely and fully.

I also applied a few dabs of dielectric grease to the headlamp plugs just for good measure.

And this is the way the low beams are supposed to look, which I believe also gives you a wider coverage of the road at night. Besides, these lamps are not the greatest, anyway, so every little bit helps. I am sure LEDs would be a tremendous help so that may become another future project as it would be to add a relay.

 Thank you for following my '76 Vette Blog!

Product Links... (#sponsored)

• 1976 Corvette Service & Overhaul Manual
• 1976 Corvette Assembly Manual
• Loctite Naval Jelly Rust Dissolver
• Low Beam Standard Halogen Sealed Beam Headlamp (Philips H5006C1)
• High Beam Standard Halogen Sealed Beam Headlamp (Philips H5001C1)

1968-1982 Corvette Headlight Actuator with Boot & Seal | Left Side
1968-1982 Corvette Headlight Actuator with Boot & Seal | Right Side