Electrical Problem - Left Turn/Stop Light Malfunction

[TXJACO]

Hi All,

I have a 2017 24RBS and 2017 F250 6.2L. On our way home from camping, my F250 indicated a "Left Turn Signal/Stop" error with the trailer. They are the LED type. Sure enough, when my wife stood behind the trailer the left turn signal dimmed when I applied brakes. After getting home, I cleaned the trailer and truck harness contacts, applied some dielectric, and found no bad ground connections. Hooked it back up and the truck left blinker then blinked really quickly!

Disconnected wiring harness and I removed the left turn/brake light from the trailer and checked for something that may have come loose. Nothing and reconnected the harness. Now I have my wife do brakes, left-right turn signals, running lights on-off, etc. and everything worked...I thought. With running lights on then off and right turn signal on, all of a sudden the left light goes dim and the error screen pops up again in the truck. Now the left turn or the left brake doesn't comes on at all; but the running light does work.

So, do I; 1) have a ground problem or 2) could the trailer left turn/brake signal be out and needs to be replaced?

Mechanical or carpentry stuff for me no problem. ANYTHING electrical, big problem for me. Thanks in advance for any advice.

Paul

[JFlightRisk]

Does the turn/brake light on the truck work normal with the trailer harness disconnected?
The turn signal and brake are the same circuit at the light.
If so, check on the truck fuse panels for trailer turn/brake fuse. There should be a diagram in your owners manual, and under the fuse panel lid. There probably is more than one fuse panel. Under the hood, and under the drivers side dash.

Next could be a bad connection in the junction box that the trailer plug harness go into. That will be the square, silver electrical box on the front of the frame.

[TXJACO]

JFlightRisk,

The truck's brake light works just fine without being connected to trailer. I checked the fuse inside the engine compartment and it's fine (1- 30 amp). The first thing I did was remove the cover for that junction box and I checked all the connections for the trailer lights. All tight and the thick white ground was attached AOK to the frame.

What was funny was when I removed the left tail light from the trailer to check the connections there, it was just hanging there. I had my wife come out and I ran through a whole series of tests (braking, left-right turn signaling, running lights on-off) and everything seemed to have been "self fixed!" Then, the left brake/turn signal dimmed and the warning indicator came on again in my truck. At some point in testing my left turn signal in the truck started clicking real fast. Now, the left turn signal/brake no longer comes on. It sounds like the tail light is bad and needs to be replaced, but these LED's are supposed to last a long time??

An wouldn't you know it...5 days past warranty!

[JFlightRisk]

Yes, LEDs usually outlast incandescent lamps. We replaced our tail light bulbs with a plug-n-plat LED panel from Command Electronics, the OEM brand for our TT. Much more visible in daylight, and should outlast the bulbs and sockets.
Assuming that there's not a bad connection in the wires to the lamp, you may indeed have a bad lamp.

[TXJACO]

Here is how the light is connected to the wires running through the trailer (see pic). I purchased an inexpensive incandescent turn/brake light and hooked it up like the LED light that came with the trailer. When I had my wife do brakes and turn signals, all the trailer running lights blinked! I tried red to red, white to green, and black to black with the same results. So, getting a new LED light sent to me. Will let you know the results.

[TXJACO]

Simply put, bad tail light. Got the new on on and working just fine!

[JFlightRisk]

Originally Posted by TXJACO

Simply put, bad tail light. Got the new on on and working just fine!

Awesome! Thanks for the update. I was curious if that was the issue.

[dornoski]

Replaced the home style non-water proof galvanized electrical box near A frame. Had some break issues so I re-wired from the drums up to the electrical junction box. Also replaced the metal box with the proper water proof junction box, all new grounds, and proper size brake wire to all brakes (4). It was shocking to see wire nuts and electric tape for connections.All new connections are crimped heat sealed. I included a couple of pictures of the junction box.

[Bob K]

I'd love to do the same thing. Where did you purchase that Pollack junction box? Amazon has many of the same style, but the Pollack has 4 screws to hold the cap on vs. 2, and just seems to be a little more robust.