my camaro did this and i never figured it out and my truck just started doing it. someone told me once that it was something to do with the A/c. i saw it happen to a suburban once and the person got under the hood and messed with the harness or something to the A/c and it stopped. didnt have the problem at the time so i didnt ask them what exactly they were doing.

 

Links not working for me...but after reading the thread from post #5 it sounds like you're on the right track. Didn't you find some wires melted or something also, or was that somebody else? If so, maybe there's still a problem there...some excessive resistance in the harness or more of the wire that is still smoked.