racerx520

iTrader: (1)

i posted about a problem that i had with my headlight not going down about a week ago. mischief told me to check the headlight module being bad and not the headlight motor itself. but is there any way i can troubleshoot to see if it is one problem and not the other? i dont want to pay 60 bucks for a headlight module and have that not be the problem, especially seeing as how im low on money as of right now.

any help is greatly appreciated!
thanks,
-brian

weaz4200

iTrader: (2)

Get a schematic and a voltmeter and check for power to both... Should give you an idea... If u got power to one n not the other... Then theres your answer.

racerx520

iTrader: (1)

alright, spent about an hour out there checking everything and heres my findings:

took apart the harness for drivers side light, found that one wire was broken (may have been reason for why the fuse blew 3 or 4 days ago), i repaired the broken wire. 12v power at rest is supplied to the passenger motor, can put a volt meter on each prong of the harness and find the 12v's. on drivers side motor, 12v power only shows up when volt meter is one one prong, and the other directly to ground, when on 2 prongs, no voltage is shown to be present.

took alligator clips and jumped from power supply side of passenger harness to motor side driver's harness and received no notice of power. did opposite and same conclusion.

put volt meter on module, showed power present.

seeing as how a wire was broken and that appears to have shorted the system enough to blow a fuse, im wondering if it had the power to blow out a motor or something else seeing as how it is 12v. the motor worked erratically the day that the headlights wouldnt go down and i noticed the tail lights werent working either.

when we checked the module it had power, but it did not flip the voltage to lower the motor down it seemed. but when the motor from passenger side was connected to the driverside using alligator wires, the motor did not move either.

i am not very good at electronics but it almost appears to me that the motor is bad, anyone else have any other suggestions?

racerx520

iTrader: (1)

any ideas?

weaz4200

iTrader: (2)

U might have a bad ground there... depending on where the ground location is...

I'm assuming u replaced the fuse....

U do these tests with loads on the motor/module?

Ive only been in school a few weeks... so electronics is new to me... But i would say, a schematic that shows u all the wires (and/or motors,relays fuses,etc) that are involved with the light circuit would help.... Then starting from the power side and workin your way around doin voltage drops could help pin point the exact problem.

racerx520

iTrader: (1)

i am not too sure if ill be able to get enough room to check the voltage drop on anything. when i originally checked the motor the screw handle on top was like cocked on an angle and kinda hard to turn. im kinda wondering if the motor like siezed a bit, then when it got power it shorted the wire or something like that

lonsal

iTrader: (2)

Get a 1987 Firebird Service Manual new from Helminc.com or used on eBay. The service manual lists the wiring schematic and trouble shooting info. In the meantime, if you've checked all your wiring and replaced your fuses, one more fuse to check, the TAIL LIGHT Fuse. That can cause the symptom you describe assuming that all the wiring including grounds and fuseable links are good.

Lon

racerx520

iTrader: (1)

ok i'll get a book...and are there fusible links on these headlight motors? i wouldnt have thought that there would be, but that would definately be a problem if there is one