Headlight Run-On
Thread Starter
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,357
From: Santa Ana CA
Headlight Run-On
I have a '91 L98 that I've owned since brand new.
The car doesn't get much use anymore and the other night I was going to take it to cruse night. The headlights were sluggish to pop up (old grease), so I used WD-40 and a rag to clean and lubricate all of the moving/rubbing parts. After this the headlights popped right up like new.
BUT, after they came up, the motors kept spinning for several seconds, with accompaning thunks from the headlights until they shut off.
Going down results in the same situation. With the hood up, you can see the motor "*****" continue to spin for a few moments.
I never recall the car doing this before I cleaned the assemblies, and it doesn't seem like it could be doing the system good. Anyone have any comments or suggestions?
Thanks
The car doesn't get much use anymore and the other night I was going to take it to cruse night. The headlights were sluggish to pop up (old grease), so I used WD-40 and a rag to clean and lubricate all of the moving/rubbing parts. After this the headlights popped right up like new.
BUT, after they came up, the motors kept spinning for several seconds, with accompaning thunks from the headlights until they shut off.
Going down results in the same situation. With the hood up, you can see the motor "*****" continue to spin for a few moments.
I never recall the car doing this before I cleaned the assemblies, and it doesn't seem like it could be doing the system good. Anyone have any comments or suggestions?
Thanks
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Easy one - the bushings in the motor/gear box are worn out and turning to dust. It is also an easy diy fix.
Here is a link - http://forums.corvetteforum.com/c4-g...r-88-96-a.html
Here is a link - http://forums.corvetteforum.com/c4-g...r-88-96-a.html
Racer
Joined: Oct 2006
Posts: 438
Likes: 14
From: Tucson/Santa Paula AZ/CA
2017 C4 of Year Finalist
Easy one - the bushings in the motor/gear box are worn out and turning to dust. It is also an easy diy fix.
Here is a link - http://forums.corvetteforum.com/c4-g...r-88-96-a.html
Here is a link - http://forums.corvetteforum.com/c4-g...r-88-96-a.html
Since the right one died, I decided to rebuild the driver's side too. Instead of waiting on an order from one of the suppliers listed(and their outrageous shipping charges), I went to ACE hardware and found that their high pressure air hose was a perfect fit. It is 1/4" ID and 1/2" OD. It is listed as impervious to petroleum products. I bought a foot ($1.17) and cut 3 pieces exactly 1/2" long to replace the factory bushings which had turned to small chips of nylon. These should outlast the factory bushings and they survived 20 years. These neoprene air hose bushings give the gear drive just a little 'give' and act like shock absorbers when the limit stops are hit. These motors work on the 'over-current' principle. When the stops are reached, the motor continues to drive until high current is sensed or a time-delay has expired.
Even after 20 years, my nylon gears were perfect. Too bad they didn't make the bushings out of the same nylon as the gear itself.
I'll add pictures when I get them uploaded.
Mick
Last edited by QZRBLU; Feb 12, 2012 at 04:47 PM.
Advanced
Joined: Sep 2008
Posts: 55
Likes: 1
Headlignt Motor "run-on"
My 86 has a little different setup within the headlight motor assembly than your 91. It could be the bushings as mentioned in another reply but it could also be one of the gears (most likely the large gear). When I opened mine up, all looked good utill I "removed" the big gear. The motor gear had worn a spot in the larger gear so kept on driving the headlight housing in the close direction even thought it was fully closed. The noise it made was pretty bad but the fix was pretty easy. Look it over carefully when you open it up.
