Mystery Wires

[Mean Green]

As 454 said, those are the wires that are ran to the back of the truck and tied up in the drivers side of the frame rails. I would bet money that's what they are, does your truck have the factory tow package? Most all GM trailer brake provision wire is red and blue, that's the color mine is although it was tucked up out of sight and much lower on the firewall.

 

[theoutlaw]

Brake controller wires, maybe. My 99 has wires under the hood that run to the rear of the truck for controlling trailer brakes. The bundle isn't that obvious under the hood, Though.

Thats what I was thinking. But I didn't see any other signs that he had an aftermarket one in here. Theres no holes under the dash where it would've been mounted and all the wiring under there is undisturbed and intact.

 

[Mean Green]

Thats what I was thinking. But I didn't see any other signs that he had an aftermarket one in here. Theres no holes under the dash where it would've been mounted and all the wiring under there is undisturbed and intact.

Your truck most likely came from the factory with those wires tied up on the firewall, so there wouldn't be any holes or disturbed wiring under the dash.

 

[454cid]

Thats what I was thinking. But I didn't see any other signs that he had an aftermarket one in here. Theres no holes under the dash where it would've been mounted and all the wiring under there is undisturbed and intact.

The previous owner never used the wires, just like I haven't.

 

[theoutlaw]

Makes sense. I do have the factory trailer package. Also I just noticed on the printout I got from the dealership with all my RPO codes.

UY7= Trailer Wiring, 7 wire, 2 lead front harness, 5 lead rear harness 7 wire trlr harn (UY7)

Thats typed letter for letter off the list. I'm assuming that this is the 2 lead front harness portion. Thanks for the help guys.

 

[radicom56]

You'll find that those wires end up at the tail light harness just in front of the rear bumper on the drivers side. They will be taped up to the harness its self on the frame rail. the ends are bare. They are there to provide dedicated 12v power for a RV 7 blade trailer connector.

 

[radicom56]

See photo

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[ChrisAU]

Hmmm mine has the same bundle in the same location!

 

[Vigh_J]

Backup beeper

 

[Hezsus]

those are 100% trailer wiring, the orange is the aux and is designed to hook up to your trailer plug aux and the aux post on the fuse box right next to it. the blue is to run into the cab for the brake controler and hook up to the plug at the back of your truck. the ends of these wires will be bent and taped up inside the plastic harness thing. and suprising enough they will be just to short to actually reach your brake plug usually.