Did resistor bypass on second truck. And replaced glow-plug relay, it definitely needed it, went to move it to my garage to do the work and it would sit there with the wait light on for about 30 sec, then would not start. New relay solved that problem.
Finished tracking down and repairing pack rat-chewed wires, about 25 wire repairs in all between the two trucks. Fortunately, he had a preference only for lighting and ground wires and didn't get into any major harnesses. I thought I was done, but in testing my lights I found the left rear running lights to be dim, and the backup lights would flash with the left turn signal. I thought maybe I screwed something up, but with a little more digging I found that the little bugger made a special trip up that hole below the left rear light just to chew through the ground wire. An easy fix, and all is working now. Glad to have both trucks up and running, and the lights working now.
I found his favorite toilet was behind the left headlight on both trucks. He liked to chew on wires while crapping an pissing in my truck.
I also removed that leaking oil sampling port.