So I've read that the 3 relay system used during these years is not compatible with the TDS rebuild kit. I did a search and found someone having the exact same problem I'm having, though he had a later 2 relay system. Whenever I flip the headlights up the passenger headlight flips all the way up like it always has but the driver's side goes halfway up, then stops. If I give it a little push past that stopping point it will go the rest of the way by itself, and it does the same thing going downward. Right now my headlights are unplugged and in the up position... if anyone can point me in the right direction as far as what to start checking out or what parts to start throwing at it I'd really appreciate it.

 

I had same problem only drivers side. It was the motor itself. When I redid the car I replaced both motors, never had the problem again. In simple terms the power goes to the motor, when the door reaches end of its travel (up or down) it hits a switch (inside motor) and reverses the power to the motor. So when it gets power again it goes the other way (opens or closes). The gear or bearing inside is worn. There cheap ways to fix it, but not worth the time to me! At the time they were only $35 each at auto parts store(3 years ago) with life time replacement if it goes bad.

 

Okay so I rebuilt mine with the kit from TDS and a new helical intermediate gear from Rodney Dickman (all nice parts and good service) and I got my headlight together.
It goes up and down just fine now but it makes a slow intermittent clicking noise when the light is in the down position, and the rebuilt motor takes far longer to raise the light than the other motor.

Does anyone have any suggestions there? If this is going to require tearing the motor open again I think I'm just gonna buy a new one.

 

I updated it to show the correct kit for these 82-86 Firebird motors. Of course, as you mentioned, you may need to replace the straight-cut gear with a helical-cut gear from a Fiero too.

Lon Salgren