Trailer lights malfunctioning (((SOLVED)))

[Merc1973]

Recently my trailer lights have been functioning. My Yukon has the factory trailer hitch and wiring . The trailer I recently rewired and installed new lights last summer. And it work Normal. I even tried to switch adapters without any change Now when I plug them in and use turn signal all of the yukon's brake lights flash as well as a third brake light however none of the trailer lights Flash. Parking lights on the trailer light do not work at one point the trailer lights were very very dim. I made a new ground connection on a trailer harness without any change. Anybody experienced this? The 15a trailer fuse under the hood looks to be intact. I will look into cleaning the connections that is a hitch and the harness by the spare tire. ( sorry for the crappy grammar, I'm posting on my cell).

 

[Fless]

Your truck has several individual fuses for each trailer light circuit, independent of the truck body. So the underhood fusebox houses those.

You can get a 7-blade test plug that will show if the 7-blade connector is functioning correctly.

Sometimes the body ground from the 7-blade is dirty so check and clean that. You can also find a good body ground on the truck and connect that temporarily to the trailer frame with one jumper cable to see if the wired ground is not good.

 

[OR VietVet]

@Fless beat me to it. What he said.

I hate working on trailer lights. Just me. My best friend recently had trailer light problems and when I got involved to help it was a PITA. He had a light assembly that was needed on the trailer, exposed wire under the trailer that I fixed when I found it tracing all wires to the front plug in. Also had a bad ground connection at the front trailer yoke area. Then one of his 2 tow vehicles had a pigtail that had a junction block in the middle of the wires and one of those had no continuity thru that block so I did a shunt around it to fix that and then I got to his other tow vehicle and the female plug in at the back was bad and so I replaced. Bad trailer lights led to repairs on three different rigs. Again, PITFA!!!!!!!!!!!

 

[Fless]

@Fless beat me to it. What he said.

I hate working on trailer lights. Just me. My best friend recently had trailer light problems and when I got involved to help it was a PITA. He had a light assembly that was needed on the trailer, exposed wire under the trailer that I fixed when I found it tracing all wires to the front plug in. Also had a bad ground connection at the front trailer yoke area. Then one of his 2 tow vehicles had a pigtail that had a junction block in the middle of the wires and one of those had no continuity thru that block so I did a shunt around it to fix that and then I got to his other tow vehicle and the female plug in at the back was bad and so I replaced. Bad trailer lights led to repairs on three different rigs. Again, PITFA!!!!!!!!!!!

 

[swathdiver]

Recently my trailer lights have been functioning. My Yukon has the factory trailer hitch and wiring . The trailer I recently rewired and installed new lights last summer. And it work Normal. I even tried to switch adapters without any change Now when I plug them in and use turn signal all of the yukon's brake lights flash as well as a third brake light however none of the trailer lights Flash. Parking lights on the trailer light do not work at one point the trailer lights were very very dim. I made a new ground connection on a trailer harness without any change. Anybody experienced this? The 15a trailer fuse under the hood looks to be intact. I will look into cleaning the connections that is a hitch and the harness by the spare tire. ( sorry for the crappy grammar, I'm posting on my cell).

Also, if you have the 7-pin connector under the bumper, unplug it from the wiring harness to clean all the dirt and dust out of it. You'll probably have to follow the wires back towards the front looking for cuts or breaks.

 

[treehan77]

Also check the lighting block up under behind the passenger side rear wheel, if it gets green schmutz it’ll do all kinda weird lighting stuff

 

[Merc1973]

Also, if you have the 7-pin connector under the bumper, unplug it from the wiring harness to clean all the dirt and dust out of it. You'll probably have to follow the wires back towards the front looking for cuts or breaks.

Sorry for the slow response. But that's exactly what it was. one of the pins of the connector behind the bumper had some bluish corrosion cleaned it up with a tiny file and some electrical cleaner and some Dielectric grease. Easy peasy thank you very much. Problem solved.

 

[Fless]

Sorry for the slow response. But that's exactly what it was. one of the pins of the connector behind the bumper had some bluish corrosion cleaned it up with a tiny file and some electrical cleaner and some Dielectric grease. Easy peasy thank you very much. Problem solved.

A good and easy outcome. Now please update the thread title with "SOLVED" so it will be easier for searchers to find your solution.

 

[Merc1973]

A good and easy outcome. Now please update the thread title with "SOLVED" so it will be easier for searchers to find your solution.

Too much time has passed by to edit OP. Sorry.

 

[Fless]

Can't use the Thread Tools drop down at the top right?