Samsonious

My gs400 was recently in a rear ended, minor body damage, I had it repaired at a local autobody place. No welding was required. I started experiencing strange electrical problems after getting the car back. Power surges, and failures. Took it in and was told the alternator was shot, but it just had a new nippondenso put in 11k ago. I'm thinking a ground wire got knocked loose during the body work. Any thoughts on where I should start?