Car is dead..help !

sounds like a fusible link is toasted.

they look like a fat piece of wire, usually (but not always) with a tag that says "fusible link"

they are designed to blow out like a fuse. when they go, you have to trace what caused them to blow before you replace them. you can splice in an inline fuse to use for testing, then when you find & fix what is blowing it out, replace the fusible link

they are superior to inline fuses because there are no parts that can tarnish/corrode.

make sure when you wire it back in you use butt connectors / then crimp / then solder / then tape / then lastly heatshrink over the tape