2001 GMC Safari won't start

My mechanic says everytime he start the van the main fuse blows. He says it'll start if he jumps it. To give you the history on this, in late June I was driving down the highway when the engine shut off. Would not restart. Mechanic replaced the ingition switch. Van seemed fine, but when I got home windshield wipers didn't work. Mechanic replaced the wiper solenoid. For about 2 weeks I would sometimes have trouble starting but it would eventually kick over. Then, again it shut off while I was driving, in late July. Had to be towed again! I noticed on the occassions when it would not start (and when it shut off while I was driving) that the fuel guage registered no fuel, though there was ample fuel in the vehicle. The mechanic cannot figure out why the fuse keeps blowing. My van has been there for 3 1/2 weeks while he has been troubleshooting. Today he tells me to take it someplace else. He is at a loss. I am frustrated.