Been watching the buddy craig headlight diagnosis videos and reading a lot of past topics on this. I had no power going to the motors with switch on, Step 1 was to verify power to isolation relay, this passed. Step 2 is to bypass the relay, this passed kind of. I now can hear the headlight motor relays clicking but still have no motor movement or sound of a stripped gear just whizzing around. Neither headlight motor operates. Going to test headlight motor relays, is it possible that all 3 relays have gone bad at. This is on an 86 gt that I just bought.
Ok, further diagnosis revealed that previous owner had not plugged in P/S relay with one connector and left the O2 style connector unplugged completely. Pass side raises and lowers as designed. Still only clicking relay on Drivers side. Now realize why p/s was unplugged, works fine going up, going down the motor just runs continuesly as in stripped gear, even with key out of car.
[This message has been edited by bonaduce (edited 01-03-2015).]
Here are the 2 videos he did on diagnosing headlights:
Go to his Chanel, and check out the rest of his videos if you have not seen them, VERY informative. These videos have helped me tremendously from replacing my ignition switch in the column, repairing window motors, replacing the PickUp coil on my distributor... you name it!
Problem solved, both motors were bad. P/S has a stripped gear and runs contunuisly in the down position, no issues in the up. D/S relay would just click, lift up slightly on the bucket and it would go up. Both replaced with know good motors and all works fine.
Ok after rebuilding the motors and reinstalling they would go up and down several times and then just stay up. Both work fine when bench tested, so I removed again and again they worked on the bench. Went through diag again and determined headlight relays shorted out. Purchased new relays and installed, same issue go up, now drivers will come down, passanger stays up. Have power and ground at pass side. So I go back to isolation relay and by pass that. All works fine. So I do the five wire relay mod discussed in another thread on isolation relay. Drive side will go up, takes about 5 seconds to kick in but goes up, down same thing. Every 15 second can hear clicking in driver side motor (not relay) and turn knob became extremely hot, so I disconnected the 5 wire relay. Passenger side I have no Idea. Power and Ground where it is supposed to be and still will not go down with bypass of headlight relay. Any ideas guys. This is on the Fiero I am selling, and don't want to sell it to somebody with any major issues, and to me this is a major issue.