TLDR: carry a spare alternator.
Once we got into town, I figured that the battery had failed, causing the alternator to stop putting out voltage, and causing our gauges to not work, especially I had just replaced the alternator not even a month earlier. So armed with that assumption, I swapped a new battery in from Napa, and lo and behold, still not gauges, and still no charging voltage.
I continued down the path of most likely issues, and arrived at needing to replace the alternator, since that is the main part of a generally fairly simple charging/starting system. Called around to the 3 parts shops in Moab, and none of them had the alternator in stock, but they were able to order one to have it in that next day, so we played tourist that night exploring downtown and got a hotel across the street from the Carquest in Moab.
That next morning, I was up bright and early waiting for the delivery driver at the store when he arrived with the parts delivery from Grand Junction. He had my alternator, so I removed the old one from the LX and had them test it, it failed the test, so I thought "Perfect! Found the issue, we might have time to go back and finish the White Rim!". That was a pipe dream apparently, as once I swapped in the new alternator in the parking lot of the Carquest, I fired the truck up and still had no gauges or charging voltage.
Convinced I got a bad alternator; I pulled that one back out and had them test it. It failed their bench test.
We were then in a bad position as it was now the weekend, and getting another alternator delivered wouldn't arrive until Tuesday, and Gigi had to be back in KC for work on Tuesday night. We ended up spending the rest of that day working on other solutions, trying to get someone to deliver an alternator from Grand Junction, potentially renting a Jeep in Moab to drive Gigi home, and then it dawned on me; the Tundra has the same engine, I wonder if I could find one of those alternators and make it work?
We talked to O'rilleys next door, and they had one! After some light modification and swapping the pulley, I R&R'ed the alternator for the 3rd time that day (4th time overall) and we had some voltage! Still wasn't showing 13.5+ volts and still had no gauges, but we had 12.8v showing with the new battery, so I decided it was time to hit the road and try to make it the hour and 40 minutes to Grand Junction, where it was showing they had an alternator that they had tested as good. We ended up making it to the Advanced Auto Parts in Grand Junction without issue, had just over 12v showing on the scan gauge when we rolled into the parking lot.
I swapped the alternator yet again (4th time that day) with their known good unit and had the same result as last time; no charging voltage, and no gauges. At this point I realized there was a deeper issue somewhere, that was potentially killing these alternators that I kept installing. Started looking though wiring diagrams online trying to figure out what the issue could be, and ended up checking every fuse, and all visible wiring before realizing that it may have been the wiring on the alternator plug itself being the issue. I removed the alternator again, and after cutting back the wiring sheath, I found this horrible splice that was obviously done by a previous owner or shop that had worked on the truck before. I bought wiring tools, fixed those wires and guess what? We finally had gauges and charging voltage!
There were some tears of joy, after messing with this for 2 whole days, we were both gassed, and ready to head towards home and out of the brutal Utah in June heat.
I do count that delay in our trip a blessing though, we were able to catch this AMAZING sunset over the Rocky Mountains on our way home, plus our first time seeing a moose in person!
