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Headlight problem, new user

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Old Aug 26, 2010 | 02:08 PM
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badbrad51106
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Default Headlight problem, new user

My 91 convertable is having headlight problems, I replaced the headlight module a year ago and everything was fine till the other day when the left headlight wouldnt raise anymore. I tested all the wires and also ran 12v right to the motor and it works. I got another headlight module and pluged it in and it worked once then same problem as before. I am only getting th 12v to the right side, any ideas what I should look at or what could be taking this module out? I am lost!!!! HELP PLEASE!!
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Old Aug 26, 2010 | 02:16 PM
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Read this thread..

http://forums.corvetteforum.com/c4-t...air-w-pic.html

Before you click over there. That thread got convoluted with two generations of light assemblies. There is an old design and a new one.

Yours needs the new advice that calls for new bushings to be replaced in your system.

One thing that is more in tune with your problem is the voltage feedback. If the motor is weak, the module reads a voltage spike and turns off the power........you may need new brushes or a new wound motor versus just new bushings etc.
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Old Aug 26, 2010 | 02:25 PM
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So how do I check for feedback? Would this feedback kill the module or what? I only have 12v coming out of the wires that go to the right motor and not to the left side??
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Old Aug 26, 2010 | 02:31 PM
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Doesn't sound like you are having problems with the bushings, more likely with the ground at the module. The relays in the module reverse the polarity to either raise or lower the H/Ls. Two bad modules in a row is unlikely, so I would check the ground. It might take a FSM to do the diagnostics properly.
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Old Aug 26, 2010 | 02:38 PM
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So where is the ground at? I didn't notice a ground unless it is in one of the plugs? What is a FSM? thanks again
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Old Aug 26, 2010 | 02:39 PM
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I guess I left one thing out, when I turn on my parking lights the headlight on the right comes up
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Old Aug 26, 2010 | 02:59 PM
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Originally Posted by badbrad51106
So where is the ground at? I didn't notice a ground unless it is in one of the plugs? What is a FSM? thanks again
FSM is short for Factory Service Manual. I saw your post about the one side coming up with parking lights, that should not happen either.
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Old Aug 27, 2010 | 08:19 AM
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I had an issue with mine, which turned out to be a bad connection with the wiring harness plug. Issue was solved with dielectric grease.
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Old Aug 27, 2010 | 08:48 AM
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Originally Posted by aminnich
FSM is short for Factory Service Manual. I saw your post about the one side coming up with parking lights, that should not happen either.

Order your FSM's online at Ebay. Often there are bargains to be found. I purchased the complete, two-volume set for my '92 in very gently used condition for under $50 bones (shipping included).
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Old Aug 27, 2010 | 01:11 PM
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My 91 had a similar problem.

I changed the Headlight Control Module which worked for about a day and I also, checked the linkage and wire connections for any shorts or chaffing.

Every night before leaving work, I had to manually raise (with the headlight **** on top of the motor) the headlight that wouldn't come up. I also, changed the headlight motor bushings and plastic gears a year before.

Out of frustration, I ordered two rebuilt headlight motors from Eckler's and they've been fine for the past three years! I even reinstalled the original Headlight Control Module since the replacement I bought failed a week later.

I figured something in the motor itself (windings, brushes etc...) was causing the motor from working properly.

http://www.ecklers.com/corvette-head...1991-1996.html

Last edited by GKK; Aug 27, 2010 at 01:19 PM.
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Old Aug 27, 2010 | 01:28 PM
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^^my thoughts exactly......Electrical motors do not last forever.

You can check if a motor is getting worn by the resistance......which by the way is what The Module reads for shutting off power when the bucket has reached the rubber stoppers....
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Old Sep 25, 2010 | 02:27 PM
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Can anyone tell me where each of the wires on the 5wire plug of the module go? I have a significant battery drain caused by terminal B and cannot seem to eliminate it. The interesting thing is that I think terminal E does the same for the opposite side of the car but causes no drain? Ideas?
Currently I have A: power up from the switch, B and E are Constant 12volt to power each motor, C is power down from the switch and D is ground. Is this correct?
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