Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Hello and welcome to JustAnswer.
My name is Vlad.
It is hard to say what exactly is causing that problem without actually connecting a TECH 2 scan tool and checking your car, but based on you description it sounds like there is wiring issue.
It could be as simple as a loose ground somewhere in the engine compartment near radiator support.
Bad ground always creates very weird problems and I have seen it many time when body shops just forget to connect something or attach and tight ground properly.
I would start from careful inspection of all main grounds in the engine compartment
I am just checking if my answer helped or if you need more assistance.