Here is a video of my left headlight. It goes halfway, and the motor continues spinning.
The gears are bronze gears with delrin bushings. I just checked them a couple weeks ago and there is grease in there too. All new. No issues.
So, what could it be?

 

My '88 does the same thing and it only has 22k miles on her!! I have rebuilt the '84-'87 headlights, but I can't figure this newer type out. The corvette shop manual gives NO direction on headlight troubleshooting......Need help guys!!!.....thanks

 

Sure would like some input C4 brothers, I need to repair mine next week!!

 

There are lots of threads on this topic. I thought mine was a little unique, due to the motor running and only going half way.

 

Thats what mine does....................damn, do I need to go see Gordon for this somewhat simple troubleshooting? Help Please!!!!!!

 

Definitely sounds like its catching. It shouldn't make that squeek/rub noise. Don't think its the headlight motor. Shift the headlight assembly a little for some clearance, see where its catching.

 

Shift it?

 

Rotate the assembly manually with the little **** on top all the way open. If it binds anywhere it will trip the relay. How tight did you replace the cap on the gear box? It needs some play. Incorrect assembly of the little washers on the shaft will stop one as well. Brass is not invincible and could have stripped for some reason. Check for changes in the hood opening clearance.

It takes 2 minutes to spin by hand to check function. It should be smooth as glass. If so we continue with modules and relays.

 

It spins freely. The washers went back in the same way they came out. Bronze gears/grease and delrin bushings were fine.
The motor spins after opening all the way, or about 10 seconds. When it closes it does the same thing.

 

Did you say it spins for 10 seconds after closing? The motor should only operate for the 1 second it takes to flip the light or the gear is free wheeling and being timed out. Also you said the gear and bushings were fine. Have you popped the case since this started? It sounds like the bushings have checked out or the gear is stripped. Just trying to help so clarify the symptom a bit. If the motor was off we could hear better too.

The good news is that a whole new headlight assembly is only like a grand.

 

It was spinning before I took it apart to look at it. So, nothing has changed since it started having issues.
here is a better video. Not quite 10 seconds, but the other side does shut down almost immediately.
http://s280.photobucket.com/albums/k...4-14-15-25.mp4

 

Yea, thats about the same sound and action both of mine make. Strange thing is, a time or 2 they have worked fine (completly opening/closing). Thanks for everyones input. I think we are getting warm.................

 

Perfect! Oh yes something has changed. The bushings are broken, the gear is stripped or the worm gear has broken out of the motor. It's timing out from a free wheeling 'tranny'. You can be looking at it in 15 minutes.

The gearbox operates on a Hall effect that stops the current when resistance is felt open or closed. You ain't got no resistance. It's one of the things previously mentioned. Bronze gears seem to be good idea but they crush bushings or mangle them. The system was designed for a nylon gear that 'gives' a little. I bet it's deformed bushings if you have the hollow kind. Use the ones at Autozone for Ford window regulators in the little Help boxes. They fit just right.

Let us know.

 

I just did this song & dance and finally figured out what makes these things do the weird things they do...

First of all, if its a 3 relay internal 88 & under motor type, the single biggest rebuild mistake is the shaft insertion in the case. The springs have to be centered and the shaft must be able to torque to one side then the other. This is what allows contact with the limit switches.

Next would be the case halves pinching or binding. This is a very common issue when 1 or 2 screws strip the case gets tweaked and binds the shaft,.

Lastly, the magnets inside can break loose from the case and ride ON the armature and cause the motor to drag and act up ultimately burning it up.

If the motor has gone weak you can sometimes breath some life into it by opening or filing the mica...the small gaps between the armature plates..cut into those and clean them out, file them out to be deeper. This will give the motor some new strength.
You can use a sharp pick, or a file if you have the smaller precision files.
Biggest thing, clean the case halves and deal with any stripped screws before closing up. I use a thin bead of pure silicone to seal out water and so the next time it can be pulled off as a strip and easily removed,. This also allows the case halves to fit tight and squeeze the silicone out to conplete the seal. Use white lithium on the gears and shaft. You don;t have to drown it, just a good glob on the gears, in shaft carriers/bearings and where the shaft lays in the case.

If you have the older motors, the limit switches may need adjustment. Bend them in or out. Keep in mind that if they are too easy to contact that throws the timing out and the motors will run out of phase. Too hard to hit and the motor does not know when to shut off. This is a trail & error kind of adjustment. You can see the action of the switches before you assemble the cases, but you do not know what the torque will be as the motor rotates and that is what matters to the limit switch and when/if it gets contact.

 

Are you talking the bushings in where the bronze gears are? Those were fine, and they are delrin. Not going to ruin those anytime soon.
I guess I can replace them and see. The right side has the same set up.

 

The fact that the gears are bronze means they were replaced. Also the ONLY way that motor continues to spin after it's closed means the bushings have been defeated by the gear or the gear is stripped.

Delrin is another word for plastic, and if your bushings are hollow the gear is running past them and spinning. The bushings make the gear STOP, OK?

There are many people who use different bushings from hardwood dowels to aluminum to Home Depot or hardware store materials to save $3. They fail. I can't think of any other way to explain your obvious problem and its solution. Good luck. tlong out.

 

tlong, relax. Its not obvioous, only to you. As many have used different materials etc. Many many write ups etc on these cars. My bronze gears and bushings have been in this car for over 10 years.
The delrin, which is a very hard plastic, yes (very similar to teflon). Mine are not hollow.
But, it is weird how the right side, replaced at the same time, is not affected. Difference in tolerance maybe.

 

I've had to replace my left and right headlight gears on my vette within the past year. Being you have the bronze gears in there it means the headlights have already gone out once and depending on what happened when they went out could help us figure out the next problem (I had one go out in the morning going into work and it sat there bouncing spinning gears for 11 hours till I got out) If the light isnt catching on the hood as you manually spin it and there doesn't seem to be any sort of exterior friction causing the binding then its obviously something internal. Crack it back open (Might be helpful to open the other one as well as a reference to how it SHOULD look) and just start picking it apart piece by piece. Its not gonna be the bushing or the gear like you said (the bronze gears not gonna grind its teeth off like the stock one and the bushings is more of a slack compensation) So it could be the actual shaft that actuates the pivot of the assembly. And since your gears kept spinning after it had reached its final point (Which it most definitely is not suppose to do) then its not tripping the relay like it should. Plain and simple bud, time to pop it open and inspect the internals. If you don't know exactly what youre looking at (Which I dont 99% of the time haha) post a pic up here and I'm sure we can figure this out.

 

Thanks very much everyone, for both of us!! I know I have enough info now to tear into them and investigate if I have to. Like I said, the shop manual shows nothing about actuation problems!!!!! Thanks so much

 

the first place to look... for motor spinning... and headlight not in position or drops...the 3 Delrin plastic bushings.. break down from heat & or grease... I have replaced them inside F body headlights in 4 Cars... there is no set time... why or when they wear...
I have scene the bushings disenigrate to powder...