97 F150 4.6 engine. Alternator blew the other day. Tested it bad. Installed new one and still wasn't charging. After countless troubleshooting I found the 20 amp fuse in a black plastic box just below the 2 mega fuses on firewall (covered by big black plastic housing) that has something to do with the alternator also. Pulled fuse and it was blown. Replaced and battery light went out and I am now getting a full charge. What a nightmare. I am one happy camper.

 

cool i have a 97 and that's what was wrong with mine