Ok my friend has a 94 v6 mustang. His mustang was not charging properly so we had the alternator checked out at Shucks and they said it was bad. So we picked up a new alternator for the car and everything seemed to work fine after we jump started it. Now a few hours later we started driving the car again and the abs gauge started going crazy and the battery guage started spiking for no reason up to or beyond the 18 volts. The spike was so bad that it blew out his right headlight bulb. My question is what do we do next to fix this problem? Is it the computer? Any help would be greatly appreaciated.