I just want to get some opinions before I buy a new door module. First, there is absolutely nothing wrong with either headlight motor. So, let's not talk about bushings and old motors and all that. Now..

When the car is started for the day, the headlight doors don't come up, or do anything at all. No motor movement, nothing. After a random amount of time, usually 5-10-15 minutes, flipping the lights off and on again, either one door will open or both. If only one opens, the second will work if you flip the lights again at some random point after that. After that, they work just fine till the next day. Remember, the motors do absolutely nothing when they don't work, like they aren't even plugged in. You can manually open them of course, but the same holds true with the motors. No action till a random amount of time later.

The plugs and connections seem fine. I replaced the module around 10 years ago with a used one when I had similar issues but I can't be sure if it was bad motors back then or the original module. Is there anything I'm missing or is the module likely the culprit? This is on a 91.

 

https://www.thirdgen.org/forums/tech-general-engine/567765-trans-am-headlights-wont.html

This is a really good post. I would do what op tried and hook each motor directly to the battery to test operation and go from there. That circuit diagram is awesome. Follow that and get a voltmeter. Anytime you have electrical issues, identify the circuit and find the diagram to find what to test

 

The link provided will not help the original poster here . Reason is , the OP has a 91 , the later style with an electronic module , and the link is for the early style with 3 relays (one for each door and isolation) and has no module .

I would troubleshoot the switch before I replaced the module . A wiring diagram for the later year lights can be found at austinthirdgen.org

 

You know, I replaced the switch too, some time back. The headlights do come on, even though the doors/motors sit silent. Does that mean the switch is ok or is there some separate deal inside the switch for the motors and the lights?

and yeah, the older models had lots of relays and the like that mine don't.

 

Oops! You learn something new everyday!

Like he said, find a diagram on line if you can for the lights and motor. From there take a power probe to each circuit and you can eventually find what gave out.

 

I'd venture to guess that it is your headlight control module. I had similar issues before. They're pretty easy to replace. No tools required and takes about 30 to 40 seconds.