Electrical short

dom.robles

dom.robles

Member
Joined
Jul 4, 2020
Messages
51
Location
Orange county
last week my turn signals and brake lights went out, i was on the road so i just stopped and was able to just replace the fuses. they worked for about another 3 minutes before the fuses blew again. i had to leave the jeep at home while i was travelling but im getting home today and will be beginning to work on it to see what i can find. i know that the previous owner used to tow the jeep behind an rv so there is a tow harness wired in the jeep. i plan to start there to look for what i believe is a short, but im just wondering if anyone has any other ideas before i dig into it. thanks
 
What fuses are popping?

Edit: Also take a minute & finish filling out your profile with the particulars of your TJ. It makes it easier for people to help you when they can see those details.
 
  • Like
Reactions: rasband
qslim said:
What fuses are popping?

Edit: Also take a minute & finish filling out your profile with the particulars of your TJ. It makes it easier for people to help you when they can see those details.
Click to expand...
#2 and #13 in the glovebox. Labeled stop lps and turn sig
 
Obviously start with any suspicious spots like you already mentioned. If nothing is found, WITH THE KEY OFF AND NO ONE STEPPING ON THE BRAKE PEDAL, take a multimeter set on continuity (preferably with the “beep” on). Probe the power side of the connector at the brake light or turning signal, and the other probe needs to go straight to a good ground. If it beeps right away, it indicates you have a dead short. Start to wiggle the harness and eventually the beep will go away. If that’s the case you’ve found the location of your short. You should keep wiggling to recreates the beep on and off. In this case you’ll have at least two bare wires shorting to ground, so if you only find one in a spot that makes the beep go away, you’ve got to keep looking for the other.
 
There are other ways to do this, btw. Circuit breakers could be used. I think harbor freight sold a little variable circuit breaker for like 10 bucks back in the day.
 
I think you're on the right track with the RV tow harness. They splice in to the circuit for the rear lamps whether it be a manufactured harness with plugs or a series of inline splices. @ItchyDong already gave some good instructions on how to find the short, you could also look for the RV tow harness... If its a manufactured harness you should be able to just remove it as a start & see if your problem goes away.

1615231972105.png

1615232284109.png
 
little update, it was a easy enough fix. the trailer harness had worn itse;t down and was grounding to the frame in front of the car and i found something similar in the rear tail lights. on the left the insulation had worn down and was touching the tub. while i had stuff apart i decided to dig into some of the po's wiring jobs and cleaned up a lot of what they did. all their electrical connections were insulated with athletic tape and loose wires connected to nothing on either end were abundant. im happy i got a lot of that out of the way and now if i want to tow the jeep im confident in the system now. thanks for the help everyone!
 
  • Like
Reactions: qslim, SoCalGlide, ItchyDong and 1 other person
Top Bottom
Back