Possible trailer plug/adaptor problem

[OR VietVet]

All my turn signals and rear lights work on my 2005 Z71. I have a tow plug adaptor that when I plugged in to the round plug at rear converts to a 4 pin or 5 pin plug for towing a trailer. Intermittently, when using that adaptor, the right side trailer lights do not work. No turn signal, no brake light and no taillights. I have used two different adaptors with the same results. I think that since all my vehicle rear lights work, I need to dig in to the tow package round plug at the back of my bumper. I am ruling out a junction block problem for the reasons I have listed. I have not looked yet. Is there a set of vehicle wires from the block to the rear vehicle lights and a separate set of wires from the block to the tow plug?

 

[Mudsport96]

It could also be in the trailer wiring as well. Bad ground, loose power wire.

 

[S33k3r]

Test your trailer plug first. If nothing, test your trailer wiring. More than likely you just have a loose wire/connection somewhere, and my money is on the trailer. From what little research I have done, the trailer plug tends to be binary; it either works or it doesn't.

 

[Fless]

The harness to the back side of the 7-blade is removable, if you get that far checking contacts.

Not that it's your problem, but I replaced my connector with a Hopkins 40920 so I'd have the 4-pin connector when needed. It's plug and play, and a physical twist install into the OE mount on the hitch.

Endurance™ Multi-Tow® GM Twist Mount 7 Blade and 4 Flat Connector

 

[OR VietVet]

More story details. I have no trailer but I do move some trailers around for my friends and I do some work on trailers in my driveway, like wheel bearing pack, and move trailers here to do that work. The right side problem is constant. It happens with any trailer I hook up.

 

[Mudsport96]

More story details. I have no trailer but I do move some trailers around for my friends and I do some work on trailers in my driveway, like wheel bearing pack, and move trailers here to do that work. The right side problem is constant. It happens with any trailer I hook up.

Ah a Paul Harvey moment lol. Well if it is multiple trailers, I guess yes it could be the connector or tahoe wiring.

 

[OR VietVet]

Ah a Paul Harvey moment lol. Well if it is multiple trailers, I guess yes it could be the connector or tahoe wiring.

Gonna inspect tomorrow. Right now is 60 degrees here but tomorrow about 10 a.m. is supposed to be the same at 60 degrees. Gonna take advantage of the nice weather and crawl around and check wiring while my girl is here to run the lights inside the rig. I have not had to deal with that junction block before. Is the spare tire in the way and I am gonna have to drop that tire for access or can I work around that tire or the block is easily accessible and tire is not in the way?

 

[Mean_Green]

Dig into the trailer wiring harness itself going to the connector. I found several wires corroded completely off. I had to cut a couple of them a few inches back and splice new wires on.

The connector itself was toast. I replaced mine with a Curt 57102 that gives the round, a 4 way flat and a backup alarm (that some people hate with a passion). I wanted it to let people know to look out because I probably can't see them.




Note, there are two wiring configurations for 7 pin connectors. One for utility trailers and one for RVs. I have no idea why, but you can make it work for either.

 

[Mudsport96]

Gonna inspect tomorrow. Right now is 60 degrees here but tomorrow about 10 a.m. is supposed to be the same at 60 degrees. Gonna take advantage of the nice weather and crawl around and check wiring while my girl is here to run the lights inside the rig. I have not had to deal with that junction block before. Is the spare tire in the way and I am gonna have to drop that tire for access or can I work around that tire or the block is easily accessible and tire is not in the way?

I think most stuff back there is easier to access with the tire out of the rear

 

[Donal]

Dig into the trailer wiring harness itself going to the connector. I found several wires corroded completely off. I had to cut a couple of them a few inches back and splice new wires on.

The connector itself was toast. I replaced mine with a Curt 57102 that gives the round, a 4 way flat and a backup alarm (that some people hate with a passion). I wanted it to let people know to look out because I probably can't see them.

View attachment 400486
View attachment 400488

Note, there are two wiring configurations for 7 pin connectors. One for utility trailers and one for RVs. I have no idea why, but you can make it work for either.

RV's require a full time 12 volt connection to power low voltage systems like lights, and to charge rv battery and applicances.