Crazy crazy problem who can figure this out

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S_LAW
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Both of my blinkers and windshield wipers work fine during the day as long as my headlights are off. However once my headlights are turned on my wipers will only work on 2 different speeds and my left blinker won't work. The wipers do whatever they want every time i hit a bump in the road they come on and since the windshield isn't wet they squeak (very very annoying). Whenever i have my parking lights on the right blinker works fine and the left works fine for a few seconds then picks up the pace as if a bulb is out. All my bulbs and fuses are fine. I don't think it could be the flasher since the blinkers work when the headlights are off. I've pulled my circuit board to the wiper motor and its fine also. What is the problem here?
Jan 6, 2006 at 3:37 AM

What to check next

Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.

Have the affected circuits' grounds and supplies checked under load while the symptom is present. Use the wiring diagram to identify any shared connections.

Guidance references and applicability

Source: This question and its visible discussion. Owner reports are distinguished from other participants' experiences. Follow-up guidance is not a confirmed diagnosis. Fluke: Diagnosing voltage drops https://www.fluke.com/en/learn/blog/automotive/electrical-automotive-troubleshooting General support for loaded circuit testing; use the actual vehicle wiring and specifications.

Read the replies · Discussion summary and reported outcome

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BADJERJIM
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Sounds like a bad ground. Headlights on sucks enough juice to pull down the power through the "iffy" ground to bring those problems to light.

Is it a Saturn or a Corvette? The plastic/fiberglass bodies of those cars are particularly prone to grounding issues as they age.
Jan 6, 2006 at 5:01 AM
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S_LAW
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no its a 92 chevy silverado
Jan 6, 2006 at 5:11 AM
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S_LAW
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i either have a bad ground somewhere or is it possible it could be the headlight switch. would a bad ground affect my wipers like that too
Jan 6, 2006 at 5:12 AM
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DARRYL
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Hello: I agree with other posts. Automotive wiring is about as bad as it gets. At each headlight there should be a ground wire to the sheetmetal somewhere. Remove them, clean and reinstall. Look for a ground strap from engine to firewall, clean both ends of it. Look for any ground wires at all, remove and clean them. When you have a problem like this the circuit is designed to have a particular current path. If the designed path for that circuit is damaged, it will attempt to complete the current path through whatever wires it can find, and there is where the problem comes in. It may not be a ground problem, but that is the place to start.
good luck
Darryl...
Jan 8, 2006 at 12:35 AM

Discussion summary

Crazy crazy problem who can figure this out

A 1992 Silverado had interacting wiper and left-turn-signal problems when the headlights were on, and bumps could activate the wipers. The owner found no obvious defect during a visual circuit-board inspection.

Reported outcome: No failed connection or completed repair was reported.

The visual board inspection did not establish electrical performance. A ground fault was a diagnostic possibility, not a confirmed finding.

Read the original discussion

AI-ASSISTED SUMMARY · REVIEWED BY 2CARPROS
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