97 f350 will not charge - 5 alternators installed still no charge. wiring problem?

you didnt check for a fusable link on the wire to the altInater??

First things first check whether the alternator is charging by starting the engine and whilst in neutral gear open the bonnet and remove negative terminal from your battery and leave the positive one in its place . If the vehicle stops then then the alternator is not charging but if it is still on then the alternator is very Ok.

But since the battery light is on as the car is on it means that the alternator has a problem . It is either the brushes are finished or the armature winding is bruised hence causing a short circuit .

Just cause its a new alternator does mean it should work. I would check the charge when running cause it could just be a bad alternator.

CHECK ALTERNATOR FUSE AND CHECK FOR DAMAGE WIRES GOING TO ALTERNATOR.NOW IF BATTERY CABLES ARE OLD THE POSITIVE CABLE MOSTLY CAUSE HIGH RESISTANCE IN CHARGING CIRCUIT CAUSING NO CHARGE CONDITIONS.MAKE DRIVE BELT IS NOT SLIPPING KEEPING ALTERNATOR FROM CHARGING.

the belt tensioner should have a slot where you can fit either a 3/8 or 1/2 drive ratchet in it to pry on it..they make a special tool to fit in it.. but a ratchet will work most of the time.

ok we have four connections at the alternator( black wire is ground) (white with blue positive direct from the battery)
and two wires connector in the regulator(yellow with black that goes to charge indicator the red light and goes to fuse 7 10a fuse block inside) the blue with yellow goes to fuse 65- 7.5a in the left fron engine comparment fuse box))#1 check for ground at the black wire= #2 check for positive at the white with blue wire (allwas with power) this wire is protected with 100a fuse is in the left front engine comparment fuse box,
remenber== check the 100a fuse
and the two fuses that protect the regulator.
when you turn the ignition switch to the on position power goes to the alternator by the yellow black wire and activate
the alternator to work.

The wires are probably broken internally, replace

Must be a broken wire or a bad connection from your alternator.

you may have a bad plug wire to the back of the alternator you can test that with a light tester but when you replace a alternator in a diesel at start up it takes about 35 secands before the unit will kick on

actually the only thing i can recomend is to have the alternator replace again for warranty and before starting the truck charge the batteries very well with a baterie charger make sure to charge them individually because with a low batterie the alternator has to put a lot of load and might burnt again
specially with dual batterie.