Park Ave. electrical issues

2000 Park Ave, 3800 engine, 100K mi. Had transmission mounts replaced at 98K and all of a sudden there are wierd electrical things happening. Idles rough in gear at stop, this started immediately after the mounts were replaced. Garage loosened mounts and made sure they were balanced out. Oil pressure says 130 psi all the time, tire monitor says low tires but will not reset(this just happened after a 3 year old battery died). Bright lights won’t dim on first pull of lever. Windshield washers stick on sometimes.

Any ideas?