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Its not charging. I'm getting 12.25 volts shut off and 12.8 volts running. I changed alternator and getting the same. What controls the voltage regulator, is it on the pcm? I'm cleaning grounds now.
The voltage regulator is in the alternator. Did you wait until the GPs had cycled off (the GPs themselves, NOT the WTS light) before checking the voltage?
Oh wait, you had that hot GPR short as well, right? So is the GP relay decommissioned for now, and not in the picture?
It has a new glow plug relay on it. I checked it both ways withe it hooked up and unhooked. I put my alternator on dads 97 and it charges. It won't charge on my truck. It will maintain 12.25 volts but won't charge to 14.3 I'm seeing on his.
Okay so I messed with it for a while tonight until I started coughing to bad to stay out. I took the alternator we put on dads truck 2 weeks ago and stuck it on mine. This was the reading on his truck.
Now this was the same alternator on my truck 5 minutes later.
I cleaned the 2 ground spots on the driver side fender, the grounds on the core support and fixed one broken one, cleaned the grounds on the passenger side fender and the one on the firewall. Tomorrow Im going to clean the 2 engine grounds after my shop floor dries. Im also going to swap batteries as well just to see if maybe I have one doing something stupid even though they both pass the load test. Other then that it runs with out acting stupid but if I run my plow I pull voltage way down. I hooked the Glow plug relay back up and it seems to be acting normal.
Does the battery light in the dash light up with the key on engine not running? The light in the dash needs to be good or the alternator will not charge.
The light has been on ever since I got the truck. I didn't really pay attention when I swapped the alternator. The reading above is the same with the glow plug relay hooked or unhooked. It was also done with both trucks at operating temps. Can you guys tell me which wires do what on the alternator? I hope to figure this thing out tomorrow because its really irritating me.
Okay so its now charging 14.4 volts, the batteries check out and I've put 45 miles on it today. I'm guessing the plug on the alternator wasn't making a good enough connection. I had unplugged it when I was trying to find the short last week. Once I probed the plugs with my volt meter pushing down on the wires it jumped to 14+ volts. I want to thank you all for the help. I haven't been messing with the powerstokes long but I'm slowly learning. Hopefully this fixes my issues.