headlight door motor

[ernbuild]

Hi gents, I am having trouble with the headlight door motor. Replaced the bushes recently and both doors were working and L/H one is fine. R/H headlight works fine but door wont open or close. Have run through the diagnostics as set out in the manual and it says to replace the motor. However the motor works fine when I test it on the bench. Have exchanged the control module also and makes no difference. The motor is getting power according to my test light, but door will not turn. Works well when I do it manually. Am I missing something?? I dont want to invest in a new motor or module if there is nothing wrong with them, as getting out to Australia is a costly exercise if there is nothing wrong with them.
Any suggestions would be greatly accepted. Cheers Ernie.:dontknow:

[lakemeadzmonster]

When you rebuilt them did you replace the nylon gear and upgrade to the 3 Teflon bushings in place of the grease that dries up ? Or did you you actually change the Motor Brushes ?

It sound like you did if it works OK manually no hesitation or slipping up or down, My thought would have been the brushes and or armature got damaged or maybe grease on it.

Does it try to open? Put your hand on the motor. Do you feel it trying to open. Yes. Put a DC clamp on amp meter around the power lead going into the motor? Compare it to the one that is working? Verify 12 volts at clip from harness. Power at the connection? OK, with a DC meter? Disconnect power connector to motor and do an OHM test on motor compare it to the one that is working. if it works on the bench and you have 12 volts to ground at the connector it should be trying to open, could be a bad connection on harness connectors.

[ernbuild]

Thanks Mate, will give it a try, and see.:cheers:

[klaptrapper]

In the motor assembly, there is a "clutch" of sorts. It is comprised of a plastic gear which is driven by the motor. it is connected to a gear which then drives the teeth of the main gear attached to the headlight cover. The motor driven gear is attached to that main gear by 3 short lucite rods, They disintegrate over time and must be replaced, in order to do that you need to remove the screws holding the "clutch' cover and clean it out of the old disintegrated rods and replace them. There was someone on the site selling these rods (better material), but I no longer have his name, as I did this job 10 years ago.
This is quite difficult to describe, but if you remove the motor assembly and take the attached "clutch" cover off, it will become obvious what has happened.
I hope this helps.

Rusty
'90 1572


Hi gents, I am having trouble with the headlight door motor. Replaced the bushes recently and both doors were working and L/H one is fine. R/H headlight works fine but door wont open or close. Have run through the diagnostics as set out in the manual and it says to replace the motor. However the motor works fine when I test it on the bench. Have exchanged the control module also and makes no difference. The motor is getting power according to my test light, but door will not turn. Works well when I do it manually. Am I missing something?? I dont want to invest in a new motor or module if there is nothing wrong with them, as getting out to Australia is a costly exercise if there is nothing wrong with them.
Any suggestions would be greatly accepted. Cheers Ernie.:dontknow:

[lakemeadzmonster]

Delrin Bushings, Ecler's #29304 $5.99 gears are $24.99.

Corvette Central has a kit that has both gear and bushing for $27.99 per set. #444325.

GM originally packed theses with a Gel that hardened and when it breaks down it looks like a spent Glade Plug-in. Also watch out for the steel ball bearing the size of a BB below worm gear, and be careful of the brushes. You can tie them up to make it easy. Also I put plumbers grease on worm gear and inside gear and bushing area, don't put to much or get it on your brushes. I haven't had a bit of trouble since I did it.

The Delrin Bushings push in pretty hard.:cheers:

[phrogs]

Every single headlight problem I have had has been the bushings disintergrating.

I just replace them no need to really spend the money on the gear.