Why does car keep blowing 40 amp fuse? on 1995 Pontiac Grand Prix

Car is slow in acceleration; windows won't roll up/down; AC won't come on-the fan blows but only out the top & bottom vents. The car has 208K miles on it. It has been running well. Spent $900 to have extensive electrical tests done, but it didn't fix the problem. My wife drove off the lot and problem returned. I won't take it back to mechanic until I get specific info of what problem might be.

Asked by for the 1995 Pontiac Grand Prix
2 answers 1 comment
Short circuit, but no way we can tell where it is without seeing and checking it. What circuit is this fuse listed for?
For $900.00 , what's the rest of the story?
Sorta curious myself!