Rob McRaf

Hi! First post on this forum. I picked up a cheap 2006 express 3500 to do some camping and tow a 21' camper. It was wired for the 7 pin connector and already had the brake controller installed, but due to an accident, the current plug was shredded. In troubleshooting and preparing to wire up the new 7pin connector (the old was was colored for the Utility Trailer type), I came up with 3 questions: (I do have a manual coming in the mail, but I figured I could make a post, I'm sure it's not the last thing I will have problems with)
1) What fuse(s) supply the 12V for the "always on" pin? It's usually red or black. I'm assuming that when the wiring got mangled that it blew the fuse or whatever supplies it.
2) For the brake controller output (blue wire on mine), what is the usual range of voltage that I should expect to see? Should it go up to 12V if it is set to maximum?
3) At what trailer/internal weight should I use the trailer/tow button?

Thanks, and it's good to be on these forums. Last time I owned a Chevy was 1996. The engine on this van is awesome, so it's just a matter of dealing with the little gremlins.

og52

30 Amp fuse under the hood fuse box

Pin 'E' on the plug.
Schematic is for a 2015. Yours maybe slightly different.

og52

Voltage is variable from the controller depending upon de-acceleration and brake (pedal) effort
Operate the manual control to check voltages.

Tow-Haul button is subjective to the operator. I don't use it under 4000 lbs as the van and my Silverado operate fine without it when towing a small load. For my 7500 lb travel trailer however, it greatly improves operation.

Rob McRaf

Thanks for the info. Found a schematic online that seems to be correct for the year, but the 2 fuses in question (13 & 50) are good, so more troubleshooting. Wouldn't surprise me if there was a break in the wire. What are holiday weekends for if not to spend them crawling around a cranky vehicle chasing out the gremlins ?

The brake controller is only putting out 6V max, but maybe it needs to sense that it is hooked up to operate properly.

Annoyingly, I just got a physical copy of Haynes manual for 1996-2007, and all the electrical schematics stop with 2005. Grrrr.....

Thanks!