OK. Settle in. This is one hell of an update.
So, last I posted, the instrument cluster was bad. The info center in the middle of it is where the CAN bus transceiver is located, and without CAN comms, almost nothing will work. So that had to be replaced.
A few days (less than a week for sure) after I got it back, it died again. Gauge jitter, wouldn't turn over, nothing worked - all the same symptoms as before. The garage came and picked it back up and they went through it all again over about four days.
This time, the instrument cluster wasn't blown, but the microcontroller that runs the info center and controls CAN comms and a bunch of other things (we'll get to all that other stuff in a minute) had been wiped clean; as in, it lost its programming. There were a bunch of blown fuses, too - head unit, HVAC controls, running lights, headlights, and a few others I forget. They reprogrammed the instrument cluster, kept it for a couple days for testing in the cold and the heat and couldn't find anything else wrong. They said they could keep it and keep testing, but at this point, I'm out for three total weeks car rental fees and a bunch of money in repairs, so i just took it back from them.
I drove to work and back a couple times. No problems. Then one morning (day four, IIRC), the running lights were out again, but everything continued to work. I replaced the fuse and everything was fine. Just a quirk, I figured. Two days later, we had some snow and then it all melted, and I lost my running lights again! This time, changing the fuse wasn't doing the trick - it kept blowing as soon as I threw the light switch.
At this point, I have to back up a step. Last 4th of July, I got in an accident. I wasn't damaged so much, but my front bumper had to be replaced. I worked it out with the body shop for them to install new front & rear bumpers that I bought, so I took the opportunity to get a set of Fab Fours Stealth bumpers installed. They hooked up my Rigid cubes and a 20" bar for me, and all was well. Or so I thought.
Turns out, the rear Stealth bumper was supposed to come with a set of license plate lights. I don't remember seeing it in the crate at all when I inspected it at delivery, so I think that was overlooked on their end. When the body shop was installing the bumper, the OEM license plate lights wouldn't fit because A) They're round; and B) They're way too small. With nothing in the crate, they scrounged up a set of lights and put them in. This was back in early August when I got it back from them, and there's been plenty of rain between then and now, and I never had a problem until now.
Turns out, after a trip back to have my local garage look over the running light circuit again and figure out why the fuse is blowing, the license plate lights weren't connected with sealed, automotive style connectors any more - they had spade terminals spliced into my existing harness, and where they made the splices was just bare wires, exposed and flapping in the breeze. It may have been wrapped in electrical tape at one point, but it wasn't there any more.
Suffice it to say that every time those wires got wet, I lost my running lights circuit. That means my headlights themselves worked, and my brake lights & turn signals worked, but none of the marker lights, the tail lights or the fog lamps would come on.
While they were re-connecting all the wiring back there (soldering the connections and using actual shrink-tube, I'll add), they discovered that one of the license plate lights themselves had since become a giant short. After removing the one bad light, the fuse was still blowing.
Turns out that by this stage, what's known as the Smart Junction Block - a sealed module containing a microcontroller, a number of FETs, and the few remaining electromechanical relays still being used inside the truck - had been damaged. Not only was the relay occasionally sticking in the Closed position, but the FET that blinks the turn signals had been damaged, and was shorted from Drain to Source. Meaning whenever that I used my left blinker while the running lights were on, the fuse would blow and I'd lose it all.
So I had to replace the Smart Junction Block as well.
After talking to the good folks at Fab Fours, they were surprised I didn't receive a proper set of lights with my bumper last summer, and are sending me a new set free of charge.
Shout out to my local garage, who other than the price of the initial repair and the price of the replacement Smart Junction Block, hasn't charged me a dime for anything they've done.
That's my story. Hope someone finds it useful somewhere along the line.
