Trailstar Passenger Side Running Light Issue

[jyu87]

Trying to isolate the issue on why my passenger side trailer running light isn’t working. Everything works (turn signal, brake lights) but the running light that turns on when my tow vehicle head lights are on. Driver side running light works just fine. I replaced the taillight, same issue.

I also noticed that the amber on the side of the passenger side (by the console) is out too. I’ve tried checking the vehicle fuse and prongs to make sure they’re not bent or out of shape. No go.

I have not tried another vehicle which is my next try to isolate vehicle or boat wiring.

Any thoughts?

[Extremeboating]

I would try what you are proposing. Could be an issue with the truck wiring for the trailer receptacle.

If it's not that, then you have a break or an outage somewhere in the wiring that runs the passenger side. My best guess if that is the case would probably be right where the trailer tongue swings.

[Lightning 6]

Coukd be bad bulb, bad ground or bad connection to brown wire.

Those marker lights are probably wired in with t-taps. Pretty high rate of failure with those because of corrosion. Check those (you can usually clamp down hard with a pair of pliers) & see if the marker light comes on…..if not remove the t tap & reconnect the marker light to the brown wire however you are comfortable. Also check the marker light’s ground connection.

[Extremeboating]

Coukd be bad bulb, bad ground or bad connection to brown wire.

Those marker lights are probably wired in with t-taps. Pretty high rate of failure with those because of corrosion. Check those (you can usually clamp down hard with a pair of pliers) & see if the marker light comes on…..if not remove the t tap & reconnect the marker light to the brown wire however you are comfortable. Also check the marker light’s ground connection.

Ah see I didn't know that (regarding the taps) T- taps are definitely a piss poor excuse for quality.

Definitely some solid advice on things the OP can check.

[blkfalc4]

The brown wires from both sides (run lts) are usually tied together at the plug. Sounds like you lost the starboard trailer side completely.
Trace the brown wire down the rails.

[Highcentered]

I'm betting you have a short near where the tongue swings. What you can do is take a 12v battery and some alligator clips and start at the tail and work your way forward until you find where the short is.

[fishon!sc]

My 2017 was doing the same thing. Sometimes it would just flicker. I knew it was not my truck. My other trailers lights work fine. It was the the plug where you plug it into the truck. I replaced it and everything is working fine now.

[StevenF01]

Check for corrosion on your plug from the trailer harness. They make an inexpensive test plug to verify if vehicle wiring is good. Autoparts store should have one.