The locks on my 2005 Chevy cobalt sound like they are trying to lock and unlock when the car is running. The locks themselves don’t move while this is happening. It has been to the dealer twice and no luck. The first time it went in, they said the left and right lock switches were shorted so they replaced them. The second time it went in they said that the ground wires were corroded and they fixed that problem. The car drove fine for a few days, now the same problem is occurring.
If the dealer fixed this under warranty, they haven’t fixed it yet. Take it back, and let them continue trying. If it’s not warranty (or they won’t warrant their work - which would be odd), see what part of it they will cover. It’s not fixed yet.
If you’re sick of messing with the dealer, this shouldn’t be that difficult for a regular mechanic to figure out. I think they’re on the right track, though…this sounds electrical.
You didn’t say where you were, so does this car suffer from excess salt spray (water-borne, coastal) or salt on the roads (winter)?
There are a few guys her who are pretty good at coming up with TSB info. Maybe one of them will pop on with some info for you.