2002 Electrical Problem

I am having an electrical crisis ... First, my battery won't hold a charge (3 batteries in 2 years). I replaced the altinator thinking this was the obvious problem and it didn't help. Addtitionally, the radiator fan won't work (so the A/C doesn't work either), neither do the door locks and the backup lights. Today as I was driving, the dash completely died on me for about 20 min. (no fuel guage, not spedometer, no temp. guage).

I had it in the shop a month or so ago and the CERTIFIED GM GOODWRENCH mechanic charged me $400 to say 'I don't know what is going on' after 2 full days of troubleshooting.

Does anyone have any ideas?

Did you get a list from the mechanic what they tried ?
If you did not , I would go back and try and find out.
Could be the ECM. See if they subbed an ecm.