i would start with the basics.i've done alot of battery cables and terminal ends.check connections at the alternator.make sure clean and tight.with battery cables oxidation can happen between terminals and posts and they LOOK clean.Now there are 3 main fuses that control the charging system.1=100 amp main fuse 2= 30 amp fuel injector fuse 3= 10 amp meter fuse.if you have a test light or a meter,you check terminals b+ A & I.with vehicle running,you should see 13.0-15.0 volts with a meter.test light should light VERY bright.