»keith
Headlight motor wiring question
Thread Starter
Racer
Joined: Oct 2002
Posts: 442
Likes: 0
From: Union ME
Headlight motor wiring question
I have followed the steps in my GM manual for a left headlight door that will not open on my 1984 Corvette. I am to the point that it says to replace the "white wire" that leads to the actuator relay. Does anyone have general (or specific) guidelines for how to do this? Thanks.
Pro
Joined: Jul 2002
Posts: 729
Likes: 4
From: Yukon OK
The early C4 head lights had some issues. I have dug into them pretty deep and I can tell you that I doubt it is the wire no matter what the manual says. Wires just don't go bad.
More likely it is a relay. They are mounted in front of the wheel on the driver's side. Or could be the motor itself.
Manually open the headlight to half way then see if it will go up or down from there. Two of the relays are the same. You can swap them and see if the problem changes sides. They control the left and right side UP direction. The other relay controls both sides in the DOWN direction.
Here is a link to a simplified diagram;
http://pg.photos.yahoo.com/ph/black8...f6.jpg&.src=ph
Start there and see what happens. Take notes and post all symptoms you see.
More likely it is a relay. They are mounted in front of the wheel on the driver's side. Or could be the motor itself.
Manually open the headlight to half way then see if it will go up or down from there. Two of the relays are the same. You can swap them and see if the problem changes sides. They control the left and right side UP direction. The other relay controls both sides in the DOWN direction.
Here is a link to a simplified diagram;
http://pg.photos.yahoo.com/ph/black8...f6.jpg&.src=ph
Start there and see what happens. Take notes and post all symptoms you see.
Thread Starter
Racer
Joined: Oct 2002
Posts: 442
Likes: 0
From: Union ME
Well, I switched the relays, and it made no difference. The right side light still worked fine, and the left side light still made no movement at all, and there was no noise in the motor. Help me out folks! Is there a relatively easy way to determine if I have a bad motor?
Racer
Joined: Nov 2005
Posts: 447
Likes: 0
From: Titletown WI
well, I -think- both sides have the same power source, but otherwise swapping the 'bad' motor to the side with the known working power would tell you if it is the motor.
IIRC, there is a "circuit breaker" of sorts inside the motor too, that could be bad. And did you manually turn the motor to see if that would "wake it up"? Just mind the fingers.
»keith
IIRC, there is a "circuit breaker" of sorts inside the motor too, that could be bad. And did you manually turn the motor to see if that would "wake it up"? Just mind the fingers.
»keith
Thread Starter
Racer
Joined: Oct 2002
Posts: 442
Likes: 0
From: Union ME
I have manually opened the headlight, and that has not done anything. By the way, can damage be done to the motor by forgetting to disconnect the power and then trying to manually open the headlight? I've done that, and the **** spins crazy in the other direction.
I think my next step will be to remove the motor and give it a good once over. I'd be just as happy to not remove the side that is good-I don't have a very good track record messing with things that aren't yet broken, and one headlight that opens is definitely better than none!
I think my next step will be to remove the motor and give it a good once over. I'd be just as happy to not remove the side that is good-I don't have a very good track record messing with things that aren't yet broken, and one headlight that opens is definitely better than none!
Racer
Joined: Nov 2005
Posts: 447
Likes: 0
From: Titletown WI
Originally Posted by efweber
By the way, can damage be done to the motor by forgetting to disconnect the power and then trying to manually open the headlight? I've done that, and the **** spins crazy in the other direction.
Another test is to remove the plug on the bad motor, and put a test light in the sockets and see if it has power. Your GM manual should say which wires have power for up and for down.
Hopefully we aren't being too redundant, you mentioned something about replacing a wire. I think I glossed over that cause it it a rare problem, typically, and a more difficult one to fix. If it turns out that no power is getting there, and the relay is good, it could be a wire, or, more likely, a bad fusable link(which is basically a wire.
)For wire repairs, I like to solder and shrinkwrap bad parts, it often helps to splice in some wire as the part that breaks is often old and brittle, but typically, unless it has been very overloads, replacing a whole length of wire isn't necessary. Crimps can be OK too, but I think shrink wrap makes connections last much longer by keeping water out.
HTH»keith
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Pro
Joined: Jul 2002
Posts: 729
Likes: 4
From: Yukon OK
Originally Posted by efweber
I have manually opened the headlight, and that has not done anything. By the way, can damage be done to the motor by forgetting to disconnect the power and then trying to manually open the headlight? I've done that, and the **** spins crazy in the other direction.
1. unplug the motor
2. open the headlight manually
3. plug the motor in (keep hands clear - it should shut)
Sorry for being so slow in posting. I just got busy.
From what you have done so far it sounds like the motor to me. There are two internal limit switches that stop the motor when the assembly is up or down. Go back to the link I posted and hit the "Back to album" button and look at the photos I posted. You will see the inside of the motor and where all the parts are.