Tow package - white wire

[thegawd]

yeah and that red wire is probably actually an orange wire. I finally found them in my burb when I had the transmission out and was laying under the truck looking at things when I caught a glimpse of an orange wire sticking out of the plastice wire loom that's directly under the brake booster. I cut the tape and opened the loom and Bamn! A blue and an Orange wire! I was finally able to properly use my dump trailer without killing its battery!

 

[thegawd]

Here I took these pics like 9 years ago and just stole em back from GMTC. So I'm laying on my back with my feet towards the front of the truck. notice exactly where the brake booster is in the pic... and remember the transmission is not in the pic because it is not in the truck. LOL this is 100% factory wiring before I opened the loom. this is also a 97 Burb...

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[bretcopsey]

Very appreciative to have found this old post, I’m digging into a poorly wired brake controller and 7pin harness installation and was afraid I was going to be in over my head cleaning up the mess. Looks like I might not be as bad off as I thought!

Most connections were twisted together and wrapped in electrical tape with the exception of the ground using a household wiring nut.

In the first picture, there is a two pin connector that had a male plug attached with the wires cut. Any ideas what that connector is for?

 

[GoToGuy]

In this thread there was an " apple and orange " problem. Before pickups came with factory " CHMBL" , aka third brake light. The white wire was used as a ground ensuring a fixed secure ground connection between trailer and tow vehicle.
Whereas after high mount brake light became standard , the extra white wire was repurposed for additional high mount brake. Therefore if you wanted an additional safety margin, splice into that wire for a third brake light on your trailer. This is an example of using the correct year service manual. The electrical section is not hard to use. It would have answered all your questions in about 30 minutes. With pictures, drawings, locations.
Don't complain about colors, but do be specific, not just green. Is it light green or dark green?
You want wiring hell, Think about bundles of 10, 15, or 25. There all white and have number/ letter ID. There's an open somewhere in a 100 plus feet of wire. Ok, enough bad memories. Good luck.

 

[Nad_Yvalhosert]

In this thread there was an " apple and orange " problem. Before pickups came with factory " CHMBL" , aka third brake light. The white wire was used as a ground ensuring a fixed secure ground connection between trailer and tow vehicle.
Whereas after high mount brake light became standard , the extra white wire was repurposed for additional high mount brake. Therefore if you wanted an additional safety margin, splice into that wire for a third brake light on your trailer. This is an example of using the correct year service manual. The electrical section is not hard to use. It would have answered all your questions in about 30 minutes. With pictures, drawings, locations.
Don't complain about colors, but do be specific, not just green. Is it light green or dark green?
You want wiring hell, Think about bundles of 10, 15, or 25. There all white and have number/ letter ID. There's an open somewhere in a 100 plus feet of wire. Ok, enough bad memories. Good luck.

(CHMSL: Center High Mount Stop Lamp)

 

[AuroraGirl]

(CHMSL: Center High Mount Stop Lamp)

I love saying CHMSL its pronounced like CHIM-ZEL at least based on a strapping lad from a 1990s buick video Ive seen

 

[AuroraGirl]

Very appreciative to have found this old post, I’m digging into a poorly wired brake controller and 7pin harness installation and was afraid I was going to be in over my head cleaning up the mess. Looks like I might not be as bad off as I thought!

Most connections were twisted together and wrapped in electrical tape with the exception of the ground using a household wiring nut.

In the first picture, there is a two pin connector that had a male plug attached with the wires cut. Any ideas what that connector is for?

looks like license plate wiring to me

 

[bretcopsey]

looks like license plate wiring to me

That was my first thought too, but this is a second plug. License plate connector is the red arrow. Yellow arrow is the unknown cut.

With all the available wiring from the factory, they ran a separate positive from a lug on the under hood fuse block and tapped into the harness at the taillight plug on the driver side. Really scratching my head on this. Trying to read the wiring diagrams on my phone has not been helpful either.

 

[bretcopsey]

I think I've figured out the cut plug - I'm working on a dually and there is a reference to "endgate clearance lights" in the repair manual which I do not have. At some point in time the tailgate was replaced with a standard tailgate.

I also found where the two grounds (black taillight harness and heavier trailer ground) had broken away from the frame and repaired them. Currently I'm only getting LH turn signal. No RH turn signal, no park lights or brake lights or reverse lights on either side. I believe I have everything back to "stock" now with the exception of a single white wire to which I cannot find a reference in the repair manual. It is in the frame rail along with the heavier gauge blue and orange wires for power and aux for trailer. Any suggestions on what this is?

 

[AuroraGirl]

I think I've figured out the cut plug - I'm working on a dually and there is a reference to "endgate clearance lights" in the repair manual which I do not have. At some point in time the tailgate was replaced with a standard tailgate.

I also found where the two grounds (black taillight harness and heavier trailer ground) had broken away from the frame and repaired them. Currently I'm only getting LH turn signal. No RH turn signal, no park lights or brake lights or reverse lights on either side. I believe I have everything back to "stock" now with the exception of a single white wire to which I cannot find a reference in the repair manual. It is in the frame rail along with the heavier gauge blue and orange wires for power and aux for trailer. Any suggestions on what this is?

that would sound right to me, or for dually fender clearance lights in a dually