The volvo

I own a 2000 S40 volvo that keeps on blowing out my engine fuse. I took it to a European car mechanic and they ran a diagnostic and didn’t find anything wrong. A week later it blew out again and I went and bought an couple engine fuses to get it to the dealership. The dealership ran about four diagnostics and it kept on blowing out the engine fuse, but they couldn’t figure out what was wrong with it. I spent 260 bucks for them to do nothing.

Every time it blows it is usually hot outside. I push on the gas and it feels I’m pushing on air. The steering wheel starts to lock up and then the engine just dies. It won’t start up again unless I change out the main engine fuse.

Do you know what might be wrong?