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Electrical problem troubleshooting

latrucker

Contributor
Sr. Member
Joined
Jul 19, 2010
Messages
647
Having a problem with my parking lights and was wondering if anyone has run into the same thing. When i put my parking lights on the will come on for a second or two and go off and the gauge cluster lights will go out as well. Signals and headlights still work. Seems to be isolated to parking lights and when they go off I can hear my electric in tank fuel pump lug down like it is taxing the electrical system. Volt meter is bouncing wildly between 0 and 12V. Obviously it is a short but my question is can it be a short in the headlight switch itself.! Let me know your thoughts before i tear into it, hoping to get some kind of direction. Thanks...
 

73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
8,778
My guess is switch. But also could be wiring into switch, sounds like maybe something shorting to ground, or something not making connection, I would pull switch and see what it looks like out of dash, plug into harness try again
 

Steve83

Bronco Guru
Joined
Jul 16, 2003
Messages
9,359
Loc.
Memphis, TN, USA, Earth, Milky Way
The short is somewhere in the parking lights circuit - probably near the taillights, where a trailer connector is/was hacked in, or where the tires have thrown up gravel/debris that has damaged the harness. The fault is tripping the headlight switch's internal circuit breaker, but the switch itself is NOT likely the problem.

It would be easier to help you if ALL your Bronco's details were in your signature.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,448
You can easily unplug the front park lights to see if the problem remains. Rear light harness can also be unplugged under the hood. That would point you to the problematic half of the system.
 
OP
OP
latrucker

latrucker

Contributor
Sr. Member
Joined
Jul 19, 2010
Messages
647
Found it!!! License plate running light was shorted. My fault, clipped the wires to remove the tailgate a month ago and forgot to reconnect them. Wire was shorted to the frame. Thanks for the help guys.
 

T-7ToNewOldB

Full Member
Joined
Dec 7, 2018
Messages
315
Those are the best problems! Easiest to fix. I love finding that kind of stuff. My brain always goes to worst case scenario first.
 
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