HELP Trailer light professionals; left blinker in-op w/lights on

[Radial GT]

I have a SR5 V6 4wd, with factory looking trailer 7 pin trailer hookup under the bumper on the drivers side.

My problem is that when I have the lights on, the left blinker does not work on the trailer. The brake light also does not work on that side on the trailer. I am using a 7 pin to 4 pin reducer, and have used 2 different reducers now so I am ruling that out. The reducers are from 2 different manufacturers, so I am fairly certain that is not my problem.

Is this something that someone else has seen?

Is there a location behind a panel where the 7 pin connector splices into the factory tail lights? It would make it easy to troubleshoot the wiring if I knew were to look. Also I am curious to were the brake converter relay is so that I can test the wires right at the source.

Normally I would just start pulling panels to find this stuff out, but it is stinking cold outside and don't want to be exploring if I don't have to. Plastic = brittle when cold.


Thanks in advance!

Mitch

 

[riceandpho]

did u make sure the trailer is wired properly and the bulbs are good? sometimes the wires on the trailer lights be wired wrong.

 

[Radial GT]

That is a good point, but the trailer is brand new. The only thing that makes me rule out the trailer is the self diagnosis LEDs on my converter.

My 7 pin to 4 pin converter has LEDs on the pins to show the power going to each pin. When the blinker is on with the headlights the pin that would be for the left blinker is very dim. The light does blink with the blinker but is VERY dim, which makes me think that it is a poor connection somewhere. If I could find where the slice location is I might just find a connection that is loose or needs to be unplugged and reconnected. That is what I am hoping for anyway.

 

[riceandpho]

ok on the 7 to 4 pin adapter i think its the same, check the harness on the trailer itself, make sure its wired correctly, like the colors on the wire is on the correct part of the light holes, like on the stop and signal, when its wired wrong , trailer light has 2 hot and one ground i think, if a hot is on the ground of the light, it will make it look dim, im sure its the trailer lighting is wired wrong, i had to do the same since my dad kinda ess up when he started adding more lights to his boat trailer, he tap in both hot and it would work funny till i redid everything. take the lights out and tell me with pics and ill see if i can help u out more, also pics of how its wired right now with the colors of wires.

 

[Radial GT]

Will do, thanks.

Certainly worth a look to see if it is done right or not. I may have a buddy stop over and have him hook up to the trailer to double check the trailer.

 

[Belovian]

Check for a bad ground. Almost all the weird trailer light issues I see are bad grounds. If a particular light has a bad ground the current will try to find the past of least resistance. good luck


Jess

 

[MikeInNH]

This is a classic bad ground problem.

 

[Radial GT]

So, I wanted to put an update on here. I was back there checking the wiring at the light on the trailer, and everything looked alright with my voltmeter. I switched the light from the other side and it worked fine!! Turns out, even though this trailer is brand new, it had a burnt out bulb right away... Can't get anything good from China anymore.


Thanks!!