No brake, tail lights, or turn signals on rear of 2018 f150

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6237225jb
Posts: 2
Joined: Thu May 17, 2018 1:50 am
Vehicle: F-150,gas,5.0 liter v8, 2018

No brake, tail lights, or turn signals on rear of 2018 f150

Post by 6237225jb » Fri Apr 19, 2019 5:23 am

On the way home, I noticed my left turn signal flashing fast. I could see my brake lights come on when I pressed the brake pedal, and I could tell the tail lights were on. I made a right turn everything was working fine. Made another left turn and left turn signal was working fine and did not flash fast this time. Made one more left turn and noticed fast flash again. Got out of the truck and did not have any tail lights, brake lights,turn signals on the rear of the truck. Front turn signals are working. Checked bulbs all were ok. Checked sockets with test light and turn signal seemed to be working, the tail lights seemed to be working, brake lights seem to be working. The bulbs show to have continuity when checked and supplied a separate 12 volt power source to them and they worked fine. Have been tracing and checking all of the wiring harness from rear to the front of the truck and have not found any problem so far except the trailer connector in the rear bumper in very wet, could this be causing some kind of short? No DTC's either.

denbo
Posts: 581
Joined: Mon Feb 06, 2017 3:00 pm
Vehicle: ford focus 16 zetec

Re: No brake, tail lights, or turn signals on rear of 2018 f150

Post by denbo » Fri Apr 19, 2019 8:00 am

Does the towing hitch socket have the disable pin? To stop things like this working when you have trailer on. In the uk they have this.

6237225jb
Posts: 2
Joined: Thu May 17, 2018 1:50 am
Vehicle: F-150,gas,5.0 liter v8, 2018

Re: No brake, tail lights, or turn signals on rear of 2018 f150

Post by 6237225jb » Fri Apr 19, 2019 2:06 pm

No, that was the crazy thing about it, when I checked the trailer connection everything was working correctly on it. I found the problem after going from one end of the truck to the other, it was a loose ground wire at the rear of the truck on the passenger side tail light harness. Thanks for the suggestion though.

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