73 F100 Electrical Problems

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Feb 26, 2020 | 12:12 PM

Another73F100Question

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73 F100 Electrical Problems

I believe I have a bad ground to my interior electronics. Does anyone have a picture or instructions about the ground connections? Thanks.

Feb 26, 2020 | 05:19 PM

Idaho Highboy

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From: North Idaho

Do you have a Haynes manual? I did a quick Internet search and it returned me diagrams. If none of those work, I can scan a couple of pages for you. Most grounds should be easy to identify regardless of a diagram. Want to expand on your hypothesis (i.e. what's not working, what is working, etc.)?
- IH

Feb 26, 2020 | 06:19 PM

meangreen92

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There's a ground behind the gauge cluster, which screws to the steering column brace.

Feb 26, 2020 | 07:38 PM

Another73F100Question

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So I've fixed the ground cable the goes from the block to the firewall (it was completely dead) and now all my gauges work... My only problem now is my dimmer switch and all cosponsoring dash lights do not work.

Feb 26, 2020 | 10:36 PM

meangreen92

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Quote:

Originally Posted by Another73F100Question

Nice! My starter would run away for the several days my truck was missing the block-to-cab ground.

Is your HVAC controls lighting up, or the lights for the headlight and wiper switches? Factory radio?
Will any of that stuff light up when you turn the dimmer far enough that the dome light comes on?

If it's a fuse, then you probably won't have tail lights - the ones which come on with the headlights. Turn signals and brake light may still work... In that case, aftermarket stereo?
Is your Brake Warning Light illuminating? High Beam Indicator?

Feb 27, 2020 | 01:06 PM

Another73F100Question

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All fuses are good. The only lights that work are the hi-beam, blinkers, and brake. All external lights are functional. There is a aftermarket radio installed.

Feb 27, 2020 | 07:44 PM

meangreen92

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Sometimes, people hook an aftermarket radio's ground to the wire for the light in the radio, and it wreaks havoc with the gauge light circuit. It could fry the printed circuit board on the instrument cluster.
The problem is in the dash somewhere most likely. It could be the headlight switch, or a bad printed circuit board, or hopefully just burned out light bulbs.

But your heater controls should light up, along with the headlight and wiper switch indicator window.