Searched the threads, couldn't find similar situation.


91 F-250 7.3, 188K miles.


Started cutting off on me driving down the road, finally figured out it was the ignition switch. Got that changed out, fixed that problem. But, at roughly the same time realized the system was not charging.


Replaced the voltage regulator and alternator, no luck. Batteries are less than 1 year old and test good.


Troubleshooting shows ignition circuit drops to 3-3.5 volts when connected to the voltage regulator, OK when disconnected.


Ideas?

 

How do your cables look? also, got any corrosion on your terminals, both on the batteries and alternator? Did you use dipole grease when plugging in your VR?

 

Cables are pretty good for 25 years old. One spot where some of the strands are coming out of the connector, but that's all. No corrosion, I keep them clean. I did not use dielectric grease when installing the VR. Where, on the connector, on the ground, on the mounting points? No evidence of grease on the original I replaced.