1992 F-350 Not Charging

MountainMan300

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I recently purchased a 1992 F-350 with the 7.3 IDI. V-Belt style, external voltage regulator.

My alternator light came on and lo and behold, I wasn't getting any output from the alternator. I put in a new one as well as a new pair of batteries. However, the new alternator is still not charging anything. I have tried two different ones from the parts store.

I will be honest, I'm a GM guy and don't fully understand the wiring on these trucks. However, I tested for continuity between the positive post on the alternator and the battery and there was no continuity. There is continuity between the ground post on the alternator and the battery.

Where should I start looking to resolve this issue? Could it be a bad voltage regulator? Are there fusible links in the wiring, and if so, where/which wires are they connected to?
 

Big Bart

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Welcome to oil burners!

1) You should always replace the regulator with the alternator. So you may want to do that in case yours is bad. But maybe it’s not based on your info above.

2) But you mention above your positive post on the alternator is not making a connection to the battery. So there is what is called a fusible link between the alternator and the starter solenoid on the fender well. (Looks like a wire but evidently burns up and cuts the connection during a problem.) Then a cable goes from the same post on the starter solenoid to the positive on the battery. That is how the alternator sends current to the battery. So you could have a bad connection (Corroded or a broken wire.) from the battery to the solenoid. But the fusible link to the alternator could have burned up inside the covering. So see if you get 12v to the starter solenoid on the fender well. (Side with +4 wires in it.) Then see if the wire from there to the alternator has continuity. Your fusible link could be toast. When mine burned up I put in a 8 or 10 gauge wire from the alt to the solenoid. it’s worked fine ever since.

Also at a minimum clean the connection on the regulator if you do not replace it.
 

Cubey

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Check the plastic connector with the 2 wires. If the plastic spring on it is weak, it can slip out from engine vibration, which disables the alternator output. The one on my RV is weak but I ran a zip tie around it and stuffed it in. It has been that way for 3.5 years and has worked fine. And it has been taken off a few times too, and still holds up.

You can get replacement a pigtail connector for not a lot:
 
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