New guy, trailer wiring question

[MotoEric]

2012 Denali w/ Z82 factory tow. At the 7 pole I have directionals, brake light, 4 ways, but no tail lights or running lights.
The PO never ran a brake controller, both the red wires under the hood are untouched and there’s nothing on the terminal posts.
Any chance that those must be connected to power the brown wire in the 7 pole?
I’ve pulled the 7 pole apart, no power on either side of the connector.

Thanks in advance!

-eric

 

[Geotrash]

2012 Denali w/ Z82 factory tow. At the 7 pole I have directionals, brake light, 4 ways, but no tail lights or running lights.
The PO never ran a brake controller, both the red wires under the hood are untouched and there’s nothing on the terminal posts.
Any chance that those must be connected to power the brown wire in the 7 pole?
I’ve pulled the 7 pole apart, no power on either side of the connector.

Thanks in advance!

-eric

Yes, the additional power comes from hooking up the red wires to the terminal post under the hood.

 

[Fless]

_
No, the two posts on the fusebox are for Aux (12v) power to the trailer, and for power to a brake controller. Nothing to do with the trailer lighting.

There should be a separate fuse for your trailer running lights in the underhood fusebox. (There are also separate fuses for the left and right trailer turn signals.) The fusebox cover should have a key on the underside, showing you which fuses go to which circuit. Find the trailer running lights fuse and, with the truck's parking lights turned on, check the voltage in and out using the test pins on the top of the fuse. Or pull the fuse to check continuity between the blades. If you have voltage there, troubleshoot the path to the trailer connector.

 

[Geotrash]

No, the two posts on the fusebox are for Aux (12v) power to the trailer, and for power to a brake controller. Nothing to do with the trailer lighting.

There should be a separate fuse for your trailer running lights in the underhood fusebox. (There are also separate fuses for the left and right turn signals.) The fusebox cover should have a key on the underside, showing you which fuses go to which circuit. Find the trailer running lights fuse and, with the truck's parking lights turned on, check the voltage in and out using the test pins on the top of the fuse. If you have voltage there, troubleshoot the path to the trailer connector.

Yes, this is correct. I forgot for a moment that he was trying to troubleshoot a lighting issue and instead zeroed in on his question about the power to the pins. I would be inclined to either look at the fuses, or hit those connectors with electrical contact cleaner

 

[Fless]

@MotoEric be sure to share the fix if you get to one; hope it's an easy one. Or toss out a question or two more.

 

[MotoEric]

Thank you, thank you!
It was the (15a) fuse....
let’s hope they’re all this easy.

if I can answer any tech questions on MotoGP, F1 or World Endurance fire away!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

 

[MotoEric]

More to follow!

 

[davidl13]

I have a 2012 Yukon xl denali , I want to add a trailer brake controller, does anyone have recommendations on make and model of controller?

I see next to my headlight switch is a hole that looks like there may have been a trailer brake controller option?? I am speculating, but I can’t imagine what else it may have been for..

My vehicle has a hitch and wiring that looks to be from the factory..

Thanks in advance…

 

[Geotrash]

I have a 2012 Yukon xl denali , I want to add a trailer brake controller, does anyone have recommendations on make and model of controller?

I see next to my headlight switch is a hole that looks like there may have been a trailer brake controller option?? I am speculating, but I can’t imagine what else it may have been for..

My vehicle has a hitch and wiring that looks to be from the factory..

Thanks in advance…

Tekonsha P3.

The factory controller would be down low:

 

[davidl13]

Tekonsha P3.

The factory controller would be down low:

View attachment 355555

Ok, I have the tow package , but not the factory controller.. what is the blank hole next to the fog light switch for? I have the same

As for the tekonsha P3, is there any other harness I need? Or just the controller?

David

 

[Fless]

I don't think so, but look at the link below and scroll down for the install video. Might want to identify your existing underdash wires to be certain they're there.

https://www.etrailer.com/Trailer-Brake-Controller/GMC/Yukon/2012/90195.html?VehicleID=2012203108

 

[gooffeyguy]

Ok, I have the tow package , but not the factory controller.. what is the blank hole next to the fog light switch for? I have the same

As for the tekonsha P3, is there any other harness I need? Or just the controller?

David

That blank hole would be where the 2wd/4wd hi/lo selector would be, but your Denali is all time all-wheel-drive so not used

 

[davidl13]

That blank hole would be where the 2wd/4wd hi/lo selector would be, but your Denali is all time all-wheel-drive so not used

Aha.. makes sense..

 

[davidl13]

The configuration tool on the tekonsha website says my truck is incompatible…

Is that true?

 

[Fless]

Did you watch the video on the etrailer link I posted? Do you have the wires under the dash to connect to the Tekonsha pigtail? If those are there and the wires for the underhood fusebox are there, you're golden.

 

[gooffeyguy]

For an electric trailer brake controller?

Any should work. They usually come with a pigtail plug that has 4 wires. Some trucks, like my 2001 Yukon, has a receptacle under the dash and you can buy a wire harness that plugs into it, then into the brake controller. The "07-13 models don't have this receptacle, but do have a taped up clump of wires up under the dash that are for wiring to a brake controller pigtail.

Section 9-65 of the 2012 owners manual

 

[davidl13]

Did you watch the video on the etrailer link I posted? Do you have the wires under the dash to connect to the Tekonsha pigtail? If those are there and the wires for the underhood fusebox are there, you're golden.

I don’t see a video???

 

[gooffeyguy]

This is from the upfitters guide

 

[Fless]

I don’t see a video???

Post #12 has a link to the eTrailer page. Go there, scroll down a little, and there are install videos right below the controller pictures.