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Firebird Headlights will go up but not down

Electronics Need help wiring something up? Thinking of adding an electrical component to your car? Need help troubleshooting that wiring glitch?

Firebird Headlights will go up but not down

Old 02-10-2019, 01:23 AM
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Firebird Headlights will go up but not down

Trying to troubleshoot a problem with the headlights. They'll rise up just fine but need to be manually cranked down. After you crank em down they will shoot back up no problem so motors are working etc. Checked the module and no cold solder joints but re-flowed them regardless, and verified the relay is functioning. I read could be the headlight switch, pinned that out and cleaned it. No issues. Then I saw something about a fuse link on the framerail? I found a 20amp bus fuse near the battery (driver side) that's just fine so I'm at a loss. Any ideas? Thanks
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Old 02-10-2019, 10:13 AM
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Re: Firebird Headlights will go up but not down

Year? There are two different systems, it'd help to know the year of the car.
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Old 02-10-2019, 10:26 AM
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Re: Firebird Headlights will go up but not down

Originally Posted by Drew View Post
Year? There are two different systems, it'd help to know the year of the car.
sorry bud thought I put that. 1989. Second gen with 2 wire motors.
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Old 02-10-2019, 01:16 PM
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Re: Firebird Headlights will go up but not down

If you look at this handy wiring diagram you will see that when you turn the headlights on the yellow wire gets +12V which triggers the module to open the doors . When you turn the headlights off the white wire gets +12V which triggers the module to close the doors . First make sure both pins "1B" and "1E" have +12V at the module connector . If so then the 64 thousand dollar question is , are you getting +12V on the white wire at the module with the headlight switch in the off position ? If yes , your module is bad . If no , your switch or the wiring connecting the switch to the module is bad ....

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Old 02-10-2019, 01:23 PM
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Re: Firebird Headlights will go up but not down

PS , don't forget that the close command (The white wire) gets it's power from the taillight circuit whereas the open command (yellow wire) gets it's power from the headlight circuit . A blown taillight fuse would cause the doors to not close since there would be no power on the white wire with the headlight switch off .

Is your 20 amp taillight fuse ok ?
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Old 02-10-2019, 01:56 PM
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Re: Firebird Headlights will go up but not down

Originally Posted by OrangeBird View Post
PS , don't forget that the close command (The white wire) gets it's power from the taillight circuit whereas the open command (yellow wire) gets it's power from the headlight circuit . A blown taillight fuse would cause the doors to not close since there would be no power on the white wire with the headlight switch off .

Is your 20 amp taillight fuse ok ?
Thanks Orange! 20amp TAIL fuse was okay. Checked the white wire, no +12V. Decided to checked the switch again with this diagram handy. Despite cleaning all the contacts I wasn't getting continuity across the upper and lower pins when the switch was off. It worked if I squeezed it so problem was in the switch. Bent down that one tab and its solid.

Headlights up and close as they should! Thanks
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Old 02-10-2019, 02:20 PM
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Re: Firebird Headlights will go up but not down

Your welcome , I'm glad I was able to help you .
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Old 02-10-2019, 05:50 PM
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Re: Firebird Headlights will go up but not down

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