2004 Cadillac DTS "Haunted"

[Scarlett'sOtherRide]

well the owner knows it really isnt haunted. But he is keeping his sense of humor through this, which is good.

Problems began earlier this summer when the humidity kicked in after a long rainy spring. Here's what's up.

Master buttons on the door will work.. then not work. Radio goes off and on on it's own. Windows go up and down on their own. Or not at all. A/C is also being "funky" Has also gotten "strange"(his word) messages on the dash info center.

He brought the car to a dealer service dept Friday and spent the entire day(6 hours) sitting and waiting to find out what the heck is up with his car. Dealing with a screaming, running child and non caring parent during 3 hours of the ordeal.
When the service guy finally called him to the desk he was told that "they dont know whats wrong with the car." BUT "every one of the modules had an error message"

Owner told me that he has pulled and replaced fuses. And that everything will work for a short time. Then it starts again. Car has "low mileage"

Now. I know what I am thinking the issue is. I had a POS Cougar that tried to kill me before I got my 69 Camaro on the road.

And I think the service dept he was at Friday, knows as well. He is bringing the vehicle to a Cad dealership Monday. (Lovely way to spend his vacation) with the hopes that they can fix the thing.

So. What I am looking for is thoughts on what is causing the "possession"
Basically to confirm my thoughts on it.
And no. I am not telling you all what I think it is. Just want to hear your thoughts. Hoping I havent lost my "car" brain over the last few years. I am hoping it hasnt been over ridden by trivial "kid who is suddenly into Barbie" stuff.

Thanks