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headlight acting funny after removing the battery

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Old 11-05-2011, 07:32 PM
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Default headlight acting funny after removing the battery

each and every time i unplug the battery in my 1990, the passenger headlight dosen't come up. it light up, but dosent ''pop up''.

I tried to check all the fuse, all the wiring, and nothing is wrong at any point.

After 10-15 min of driving , it pop's up all of a sudden . It does that EVERY TIME.
once it pop up, it never cause problem untill i unplug the battery again.


cant figure out why it does that, and why that problem solve by itself after a couple of minutes.


any ideas?

thanks
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Old 11-05-2011, 08:02 PM
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Sounds like the headlight motor is trying to ground itself through an alternate path. As in, its intended ground path is compromised either through corrosion, or by some other gremlin.

If you can get your hands on a few feet of about 12 ga wire with alligator clips on either end, try this:

Clip one end of the wire to the ground wire of the headlight motor. The other end should go to a solid ground, like the engine block.
Then disconnect and reconnect the battery to re-create the problem, and try the headlights.
If the problem goes away, trace and clean the ground connections associated with the motor assembly.

Check your ground connections using a voltmeter, with the key off. You should see 0.00 ohms across the ground connection and the chassis/engine block/battery "-" terminal.

In the unlikely event the problem persists, try the same method with the 12V feed. In that case, take the other end of the wire straight to the bolt securing the 80 amp fuse in the underhood fusebox..

Last edited by Godless Commie; 11-05-2011 at 08:08 PM. Reason: spelink
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