New to list, problems with trailer lights

[Peter K]

Hello,

My name is Peter K and I live in a lil community called Hollywood, SC thats west of Lake Murray. I have been to 2 trailer shops today and 1 mechanic and my truck has them stumped. I own a 2005 Silverado 3500HD dually Crew cab. The issue I have is that there is no power to the trailer hitch socket in the truck for the Left Hand Turn signal, Brake Light, or Running Lights. This is only on the left side... I have to date replaced all the fuses between the box under the hood and the fuse box in the console side panel. I'm a bit perplexed here.

Where do I need to look next?

Thanks

Peter K

 

[2004LB7]

Welcome

Underneath the bumper where the trailer connector is, there are some additional connectors for the trailer along the harness. You may need to take those apart and inspect, clean, test for power, etc

 

[Peter K]

Welcome

Underneath the bumper where the trailer connector is, there are some additional connectors for the trailer along the harness. You may need to take those apart and inspect, clean, test for power, etc

Than ks for the tip. just checked that out. Nothing seems to be amiss. Its quite the rats nest of wires under there..

 

[2004LB7]

Yes there is. I've found my fair share of issues in that location.

 

[Ron Nielson]

If the power is present at the front-end fuse but no power at the rear end, my first guess is that the wires have been broken or cut. I am assuming that someone has checked a wiring diagram, identified the ground for that side, and made sure the ground has good contact.

 

[Bdsankey]

Than ks for the tip. just checked that out. Nothing seems to be amiss. Its quite the rats nest of wires under there..

Has someone spliced into the harness to add an in-box connector for say a gooseneck/5th wheel?

 

[Peter K]

Has someone spliced into the harness to add an in-box connector for say a gooseneck/5th wheel?

yes there is a 5th wheel plug in the bed that came from the factory

 

[Bdsankey]

yes there is a 5th wheel plug in the bed that came from the factory

Are you sure it's factory? I haven't seen that on a 2005 in our area, usually it's guys adding them since there wasn't (to my knowledge) a factory 5th wheel/gooseneck package.

 

[Peter K]

Are you sure it's factory? I haven't seen that on a 2005 in our area, usually it's guys adding them since there wasn't (to my knowledge) a factory 5th wheel/gooseneck package.

It appears to be because its all the same wiring going up to the location in the left rear corner of the bed by the tailgate

 

[JoshH]

I don't want to insult you or anyone who is helping, but I want to be thorough with my answer. Are you checking the trailer brake and turn fuses? The trailer wiring has its own fuses that are separate from the fuses for the lights on the truck. Also, the wire that feeds the running lights is a single wire that powers the entire trailer. It isn't side specific. If your trailer has no running lights only on the left side, it could be a ground issue at that light (unless I'm misunderstanding your post on that part).

 

[Peter K]

Yes I have replaced all the fuses associated with the trailer connector in the truck. I spoke to a friend last night who said that i needed to look at the wiring under the main fuse panel in the engine compartment for a broken lead...

 

[Bdsankey]

Yes I have replaced all the fuses associated with the trailer connector in the truck. I spoke to a friend last night who said that i needed to look at the wiring under the main fuse panel in the engine compartment for a broken lead...

To Josh's point, did you check them for power or just replace fuses? Throwing parts at a problem doesn't always fix it, a good multi-meter and test light will likely solve your issue.

Start at the fuse box and work toward the rear of the truck until you no longer have power/continuity front to back.

 

[Peter K]

I have power at the fuses. Its lost somewhere past them....

 

[2004LB7]

Trailer wiring is not that complicated. The harness runs from the fuse box down the frame and to the trailer connector. If someone added a in-the-bed connector then typically they disconnect the back side of the stock trailer connector and put a splitter in it that runs up to the bed. Take those apart and test for voltage

 

[TheBac]

Moved to Towing section. Thread name updated to issue topic