Fun weekend doing Truck Things.
I needed to figure out why I was getting DTCs about the trailer brake controller. I had looked at the DTC and read a little on it when I first brought it home (it was one of the known issues with the previous owner, and one I leveraged to get the truck cheaper) - it ranges from bad TBC, corroded or otherwise mangled wiring, or a bad 7 pin on the truck. Didn't want to deal with it then, because I didn't have an immediate towing need so it was easy enough to stop caring about. Finally had some hauling coming up and needed to look into it.
The first thing I did was just check voltages at the 7-pin. Nada. I skipped the crawl under the truck and went to the fuse box. Checked the fuse for the TBC, it was fine. Replaced it anyway just for giggles, but of course, no luck.
Chased down through all the electric for a couple of hours. Took a brake (heh, heh) from it and went to look up schematics. Turns out, there's
two fuses for the TBC - one for the module itself, and the other (the one I had checked) is for brake signal and turn signaling. Ugh. Crawl back under the dash and ... that 2nd fuse was missing entirely. My guess, as much as I can put one together, is someone popped the fuse at one point or another and just never replaced it? I could almost understand a popped fuse being in there, but since it was missing entirely, someone intentionally did that.
Grab another 5A fuse, toss it in, the DTC for the controller immediately heals. Interestingly, so does my reverse sensor DTC (another one I was going to fix "someday").
Feeling a little dumb that it was just a fuse in the end, but, also glad it wasn't something more annoying. Hooked it up to a trailer and didn't have an issue with it all day though. There's a few settings for my controller which I need to read up more on - the normal gain amount to adjust, a three "initial output" setting, and a setting specifically for electric-over-hydraulics (which, none of the trailers I'd use have anyway).
The built in engine/exhaust brake is
really cool too. First pickup that I've had with it, and turning it on while descending a grade is very nice. Plus the turbo geometry changes and you get some really pleasant turbo-whistle going
