Interesting day and still early afternoon.
Yesterday I was able to get new transfer switch control wired up. When it didn’t test out with a 9v battery, I just called it a day, figuring it was my poor memory that I used a 9v last iteration. So this AM, neatened up the wires while waiting for run to PO and configured test using 12v from my diesel pump battery. Not good. Smoked a black wire. Figured probably me with a bit of slop. Make new wire, tried again and fried red wire. Figured a good time to make PO run.
Got dogs loaded into truck. Dash lit up with assorted error lights, same as before with some additional. Truck started but with some very minor engine surging. Shut it down, restarted. Figured I go to PO and just leave running in case. Barely got truck out of garage when it died

. Would have to guess earlier problem not solved. Several calls into dealership. Waiting for them to arrange the tow.
So back to transfer switch project. Checked and rechecked everything and appeared relay was operating NC instead of NO. Doubled checked that the colored leads for relay block were same order as my working relay. No joy - took a break. Turns out the new relay has same color wires but arranged differently. Once I got it sorted out by the terminal #s appears to be working. Taking another break while epoxy sets on my terminal blocks and I await the tow call.
Just another day coming up a bit short. Ahhhhhh retirement