I'm not a diesel mechanic, but have been an aircraft mechanic for a few decades now. I have run across this same gremlin in aircraft on several occasions. You have a weak/bad connection somewhere. If you can figure out the electrical path of your common failures, it could possibly be narrowed down to one connection point. Unfortunately you are limited to the info the OEM will give out, so you may be stuck with the dealer. Write a journal of all your symptoms no matter how insignificant they may seem and find a competent mechanic. Your truck can be fixed, your just need to feed the right info to the right mechanic... ... ...
Is Mike Mullenax still on here? if so maybe he can help.