A few years ago I posted this on another camping forum. I thought that someone on JOF might benefit from it, so here it is.
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Yesterday I got the trailer out of storage, and as I'm pulling it home, I notice that no matter how many times I hit the tow/haul mode button, the light never came on. So a quick Google search, and a look at some truck enthusiast websites, determined that 99% of the time it's just a broken wire. I watched some YouTube videos that show the procedure, and I'm posting my experiences here so hopefully anyone else who has a GM vehicle and encounters this problem can do the same thing, and save some time and money.
The steering column has to come apart. Removal of the knee bolster and instrument panel makes this a lot easier. Keep an eye out for hidden screws.
See the orange wire? That's the culprit. It goes to the tow/haul button on the end of the shifter. This is just a momentary switch that tells the PCM to switch to the towing profile. Inside the orange wire are two smaller white wires.
Here's a closeup of the orange wire. In my case, both white wires were broken; one was held together by just the insulation. I spliced a patch between the two parts using some speaker wire. Since these wires don't really carry any serious power, that will do. The 4" of wire I added will also add a little slack into the wire so it won't happen again. (Sorry about the dog hair; I didn't notice it until after I took the photo. When you have a husky, it gets everywhere.)
I spliced the wires together, soldered them where I could, then used heat shrink tubing and covered the entire repair area in electrical tape. Turn the key on, press the button and success!
Overall, I'd say the difficulty of this repair would be 3/10 for anyone comfortable with working on cars. The button and wire aren't available on the market, so the only other way to repair this would be to replace the entire shifter lever.
Linear Mode
