Headlight issues

1989 NISSAN 300ZX
170,000 MILES • 3.0L • V6 • 2WD • MANUAL
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JORDANNGIAU
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Initially, the high beam and low beam would only work when i switch to 2nd position on the combination switch. Only fog lamp would work in 1st position, Low beam does not work.

After attempting to fix this issues, i have removed the combination switch to clean the contacts. After putting things back together, when i put the negative pole back on the battery.

Both the high beam and low beam lit up straight away while the switch is in off position without the keys in the ignition switch.

I took out the combination switch to give it a look again. After putting everything back, now only the driver side high beam and low beam lit up when i connected the battery while the passenger side worked normally.
Mar 30, 2021 at 8:38 AM
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JACOBANDNICKOLAS
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Hi,

Because or of the model year, my manual is extremely vague. However, it sounds like you found where the problem is, the switch. Have you replaced it yet? Also, did you check the wiring while it was apart?

Let me know.

Joe
Mar 31, 2021 at 8:02 PM
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JORDANNGIAU
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Thanks for the reply. Vehicle is a Z32 2+2 Targa Top.
Anyways, I do not suspect the switch for now because I tried removing the switch from the loop by not having the switch connected to the harness and connecting the battery still lit up the driver side Low and High beams.
Mar 31, 2021 at 8:13 PM
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JORDANNGIAU
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Also tried switching the Left and Right side headlamp relays, still the same result. Also tried switching up fuses for the headlamp fuse under the hood and illumi fuse under the drivers foot well.

Can it possibly be a ground issue? How many grounds are there throughout the headlamp wiring circuit?
Mar 31, 2021 at 8:18 PM
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JORDANNGIAU
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Another reason why I do not think is the switch because I did a continuity test with reference to the Factory Service Manual for the switch and it passed flawlessly.
Mar 31, 2021 at 8:19 PM
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JACOBANDNICKOLAS
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Hi,

It sounds like a short to power. Disconnect the battery and check for continuity to ground at the switch wiring. See if any are shorted to ground.

Joe
Mar 31, 2021 at 8:55 PM
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JORDANNGIAU
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so I had to connect the positive lead to the wiring harness and negative lead to the body of the car?
Mar 31, 2021 at 8:56 PM
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JACOBANDNICKOLAS
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Hi,

That sounds correct. You need to see if power from the multimeter goes through to ground.

Let me know.

Joe
Apr 1, 2021 at 6:18 PM
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JORDANNGIAU
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I have located the problem, it lies at the indicator stalk where there is an option for high beam. The internals are made of plastic which degrade overtime. The housing for the high beam selection was observed to be warped out of shape.
Apr 1, 2021 at 6:20 PM
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JORDANNGIAU
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I checked the switch which shows continuity between positive lead on wiring harness and the body of the car, which means it's either a short circuit between the wires or a switch is turned on. Chose to diagnose the simpler route and located the problem. Thanks for the guidance throughout the troubleshooting process.
Apr 1, 2021 at 6:21 PM
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JACOBANDNICKOLAS
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Hi,

You are very welcome. I'm glad you found the problem. Please feel free to come back anytime in the future if you have questions. You're always welcome here.

Take care and Happy Easter,

Joe
Apr 1, 2021 at 6:41 PM