C-3 headlight motor

[James G.]

My passenger headlight seems to be sticking which it never did before. It will open if I reach under and push it up and just the opposite to close it. Is it possible that it could gum up from not being used or is it worn out? If it is gummed up can it be cleaned without removing it from the car?

[Kevin M.]

Re: C-3 headlight motor

C-3 headlights run off vacuum, some of the parts house and your shop manual have great diagrams for trouble shooting the system.

KM

[Pat M.]

Re: C-3 headlight motor

James - unless I'm mistaken, your headlight assembly is operated by a vacuum actuator like my 70, not a "motor". So I would guess that you have a vacuum problem, e.g., relay, actuator, hoses.
Now, there are obviously mechanical linkages on the assembly which could be in a bind which could cause your problem. But, without more info, my guess is it's a vacuum problem of some sort.

[George D.]

Re: C-3 headlight motor

Most likely a vacuum issue. However, if you put vacuum directly to each vacuum canister port (I forget which port is for up and which is for down) and it goes up and down that would eliminate binding and let you know the vacuum canister is working.

[Jack H.]

Re: C-3 headlight motor

That approach to diagnostics will work! But, understanding how the vac system is laid out and works can help even more... Two issues to deal with:

(1) The RH or passenger side headlight SHARES its servo vacuum (the vac that actually does work to open/close things) with the WS wiper door. Minor leak(s) in the wiper door vac circuit can/do affect the RH headlight!

(2) The entire vac system starts with a plastic filter (between the intake manifold and the check valve). These were meant to be replaced periodically as part of routine maintenance. Very few new owners know about the need to keep the vac filter fresh/new... When this filter becomes plugged with dirt/grease, it reduces the RATE at which air can flow through the vac system and the first components to act erratically due to loss of vac volume are those furthest away from the vac reservoir + those that use the greatest amount of vac in their operation (interpret that as the RH headlight)...

To check, pull the white plastic vac filter. Hold it up to the light and look through it. If you see clean white light, you're good to go. If you seen dark grey/black, your filter is old, aged, dirty and needs to be replaced. If you see raw daylight, the filter's internal element was used SO LONG and became SO dirty/clogged that the element 'ripped' out and was sucked into your intake manifold!!! Not good...

If the car is driven regularly, you should be replacing vac filters once or twice a year depending on the mileage you drive.

[Joe L.]

Re: C-3 headlight motor

My passenger headlight seems to be sticking which it never did before. It will open if I reach under and push it up and just the opposite to close it. Is it possible that it could gum up from not being used or is it worn out? If it is gummed up can it be cleaned without removing it from the car?

James-----


The most likely problem is a failing actuator seal. Never available from GM, these seals can be purchased from Corvette parts sources for about $15. They are easily installed and will solve about 90% of the actuator problems.

[Michael D.]

Re: C-3 headlight motor

...The most likely problem is a failing actuator seal....

I agree.

[James G.]

Re: C-3 headlight motor

Thanks to all for your input. I guess I should not have called the actuator a motor. I knew the headlight system operates by vacuum but motor came to mind when I was typing this post. I will check the filter and do some research on the actuator seal to see what type of project that will be. Thanks again.

[Joe L.]

Re: C-3 headlight motor

Thanks to all for your input. I guess I should not have called the actuator a motor. I knew the headlight system operates by vacuum but motor came to mind when I was typing this post. I will check the filter and do some research on the actuator seal to see what type of project that will be. Thanks again.

James-----


Actually, these type of devices are sometimes called vacuum motors. So, you were not completely incorrect with your reference to the term "motor".

The filter is VERY easy to check. You will find it in the line between the engine and the vacuum tank. It is white plastic. Most of the time, when you inspect this, you will find that there's no filtering material remaining. In other words, you'll be able to look right through the filter without obstruction. Of course, this means that the filter should be replaced. However, in this circumstance, it could not be responsible for any problem you have with the headlight actuator.

[Jerome P.]

Re: C-3 headlight motor

Joe, Like James my passenger side head light door sometimes opens, sometimes opens only half way, and then sometimes only opens a little. When it does not open correctly the slightest nudge will allow it to open the rest of the way. they all closes fine L/R head light doors and wiper door.

Do the mechanical hinges, etc ever need lubrication or should I just figure it is a vacum problem?

[Jerome P.]

Re: C-3 headlight motor

My passenger headlight seems to be sticking which it never did before. It will open if I reach under and push it up and just the opposite to close it. Is it possible that it could gum up from not being used or is it worn out? If it is gummed up can it be cleaned without removing it from the car?

James, Did you get the door to work properly? If so what was the problem and what did you do to resolve?

[Joe L.]

Re: C-3 headlight motor

Joe, Like James my passenger side head light door sometimes opens, sometimes opens only half way, and then sometimes only opens a little. When it does not open correctly the slightest nudge will allow it to open the rest of the way. they all closes fine L/R head light doors and wiper door.

Do the mechanical hinges, etc ever need lubrication or should I just figure it is a vacum problem?

Jerome-----


Several of the pivot points in the system use nylon plastic guides which are "self lubricating". However, these do wear and, ultimately, break. Otherwise, it would not hurt to lubricate the pivot points. However, I don't think this is the source of your problem. More likely, it's a case of defective vacuum seals on the actuators. Replacement seals are available in the Corvette aftermarket for a nominal cost.

[Jerome P.]

Re: C-3 headlight motor

Is there a way of testing for bad seals?

[Joe L.]

Re: C-3 headlight motor

Is there a way of testing for bad seals?

Jerry------


No way I know of. I'd just replace them and see what happens. They are not very expensive and they are not difficult to install.

[Jerome P.]

Re: C-3 headlight motor

Thanks Joe. As always you are the go to guy.

Jerry