So after doing some major repairs on my 04 mazda 6 i ran in to a slight problem my dad tried to start the car last night and accidentally connected + to - and - to + from a jumper battery and blew the main fuse. So Today i went and changed the main fuse but it keeps blowing after couple minutes of the car running also i have nothing coming up on radio and i cant connect my computer to check the fault codes to it? Any ideas where to look?

 

Most likely fried the PCM &/or alternator.

Big cost for small mistake.