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Join Date: Sep 2013
Location: Huntsville, AL
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Confirm My Low-Beam Diagnostic Logic

I've been studying this in the forums for a bit and want to make sure my logic is sound before I remove my steering wheel:

Tonight, while driving, both my low-beams suddenly went out. High beams and all other lights work fine. I didn't notice any burning smell or smoke.

All fuses are intact and I have had the JWest headlight relays for about two years.

I swapped my headlight relays to make sure a bad relay wasn't the cause. The high beams still worked and the low-beams still did not.

Current is passing through the high-beam fuses when the high beams are on.

No current is passing through the low-beam fuses when the low beams are on.

Do you think the next logical place to look is the turn signal stalk? I had to adjust the contacts a few years ago to keep the high-beams from turning on whenever I went over a bump. Could a similar contact problem keep the low-beams from turning on?

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Old 03-06-2016, 05:20 PM
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Try swapping the jwest relays from hi to low yet?
You need to check the input to them is working normally as the output from the relays now supplies the current/voltage to the fuses.
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Dennis
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Old 03-06-2016, 06:17 PM
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I did swap the relays to see if the opposite beams would begin working if that's what you mean. Unfortunately, the low beams still didn't work and the high beams still worked. I was really hoping it would be a simple relay :/
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Old 03-06-2016, 06:22 PM
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I bet it's the light switch! Needs another little adjust or replacement. I guess you added the relays just too late.
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Old 03-06-2016, 06:35 PM
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usual reason for hi beams to work and low beams to not work is the turn signal/high beam combo switch on the steering column
Old 03-06-2016, 07:59 PM
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Check where you connected the original yellow wire into the corresponding low beam input Jwest relay wire, maybe it came loose?
Also a great place to check for voltage signal when low beams are on.
If no volts there, then it is likely the turn signal switch.
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Dennis
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Old 03-06-2016, 08:19 PM
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You should be able to use a test meter to verify that no voltage is being passed through the turn signal switch by testing at the input to the relay while activating the switch. The problem could be just a bad connection to ground from the relay input. If you see no switched power with a test meter (or test light) at the relay input then you know the problem is at the switch.
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Old 03-07-2016, 06:30 AM
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Keep, multimeter showed zilch. New switch en route. Now, I've just got to start researching how to install the new wiring it comes with :/
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Old 03-07-2016, 06:46 PM
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It will be fairly simple. Just make notes and take photos as you remove wires as to where they came from while you get upside down in the cockpit.... The 6 pin plug is easy. The ones on the back of the light switch are a pain. Disconnect your battery before you start...

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Dennis
Euro 1978 SC Targa, SSI's, Dansk 2/1, PMO ITBs, Electric A/C
Need a New Wiring Harness? PM or e-mail me. Search for "harnesses" in the classifieds.
Old 03-07-2016, 10:35 PM
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