Hi good friend mine has rang looking for advise, his battery went dead on his vw bora tdi pd the other day an as you do put jump leads on it but put them on wrong way, he though he just blow the alternator but he got it fixed today an its charging but the battery light an alternator workshop is still flashing when started, the radio isn't going aswel, he plugged it in but no codes coming up, does anyone have any ideas what could be damaged or need replaced? thanks

 

A main fuse? Switch wire from alternator? Light in dash? Ecu?