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Old 01-31-2018, 08:32 PM   #1
tim71
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Wipers,Turn Signals, Backup lights, Fan Blower Don't Work.

Need some opinions. I'm rebuilding a 71 K1500 and have a problem. Every thing electrical that should work with ignition key in on position won't work. Earlier in the build, all of these items worked perfectly. The truck starts and runs OK, and every thing that should work with key off works good(headlights,flashers,dome light). The dash gauges are also working good. I haven't started trouble shooting yet, I'm hoping someone might steer me in the right direction.
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Old 02-01-2018, 12:30 AM   #2
dmjlambert
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Re: Wipers,Turn Signals, Backup lights, Fan Blower Don't Work.

12 Gauge brown wire from the back of the ignition key switch supplies the part of the fuse block that controls those things.

Turn the key on and check with a voltmeter to see if you have 12V between chassis metal and those terminals bottom and left of the fuses that I'm pointing to in the picture. If 12V there, check fuses there. If no 12V there check the brown wire condition. Trace it back to the ignition switch. You should be able to stick a sharp voltmeter probe next to the brown wire at the ignition switch or pierce the brown insulation to check for voltage. You can also use a probe type test light.

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Old 02-01-2018, 11:23 AM   #3
VetteVet
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Re: Wipers,Turn Signals, Backup lights, Fan Blower Don't Work.

Quote:
Originally Posted by dmjlambert View Post
12 Gauge brown wire from the back of the ignition key switch supplies the part of the fuse block that controls those things.

Turn the key on and check with a voltmeter to see if you have 12V between chassis metal and those terminals bottom and left of the fuses that I'm pointing to in the picture. If 12V there, check fuses there. If no 12V there check the brown wire condition. Trace it back to the ignition switch. You should be able to stick a sharp voltmeter probe next to the brown wire at the ignition switch or pierce the brown insulation to check for voltage. You can also use a probe type test light.

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Nice job with the diagnosis and the pics. I saved them to my hard drive, hope you don't mind.
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Old 02-01-2018, 11:38 AM   #4
Richard2112
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Re: Wipers,Turn Signals, Backup lights, Fan Blower Don't Work.

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Nice job with the diagnosis and the pics. I saved them to my hard drive, hope you don't mind.
I did also.

Yes, nice job on the diagnosis. That's saying something coming from VetteVet, who I know has walked members through their electrical difficulties before.
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Old 02-01-2018, 12:14 PM   #5
dmjlambert
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Re: Wipers,Turn Signals, Backup lights, Fan Blower Don't Work.

Thanks guys. tim71, let us know how it goes. Also see what you get with the key in the accessory position (that position we rarely tend to use turning key to the left).
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Old 02-01-2018, 04:33 PM   #6
tim71
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Re: Wipers,Turn Signals, Backup lights, Fan Blower Don't Work.

Good news! I've identified the problem, but not corrected it yet. I turned the ignition switch to on and also turned on the windshield wipers. I reached under dash and jiggled the wires coming out of the ignition switch, and the wipers began operating. The same procedure made accessories work with key in accessory position. When I put ignition switch back in truck during build I only replaced the bezel and key cylinder, as I wasn't aware of the actual switch having any problems. As far as I know, this is the original ignition switch. Would you replace it or can the original be repaired easily? Thanks for your help, it sent me in the right direction right away.
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