Volvo Repair: Wires crossed on Jump start, dozen cars, diagnostic computer

Question
My son has a 99 S70 and after letting the car sit for a couple weeks the battery needed a jump to get the car started. However he and his friend goofed and connected the positive to the negative and terminals and of course it made a big spark. Then they hooked them up properly and the car started fine and seems to run fine, however most of the dash warning lights are now illuminated. How do you suggest I trouble shoot this problem. I am fairly experienced back yard mechanic and have restored a dozen cars from start to finish, but I am totally green on Volvo electrical. Any help would be appreciated.

Answer
Most likely the computer inside the cluster fried.  This one could be as simple as a cluster replacement but there are plenty of other things that could have been damaged that you can't see.  I would recommend at least taking the car to a dealer for a quick diagnostic evaluation.  Generally its about $100 or so and will take about 1-2 hours.  The will hook up to the diagnostic computer and do an entire readout of all the electrical systems.  Once you get that you will have a complete evaluation of everything that cooked.

James