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1st Gen. Ram - All TopicsDiscussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.
1992 W250 5spd 12 valve. I’ve been running around this charging issue for a week. Bought the truck, had a no charge problem. Came down to a PCM. Hooked up an external regulator. Now overcharging (steady at 15.3v). I’ve been told this is good and bad. Had a guy tell me that OEM regioator from dodge will fix it. Nope, $70 later for that and still at 15.3 . I have a new alternator, new battery, and every single wire that has to due with the alternator is new. Ground running from battery to regulator. Still overcharging. What could I possibly be missing ??? Any help is greatly appreciated
Sounds like the alternator is running full power to the battery unregulated. You need a 12V source to the center pole on the regulator and to a field terminal on the alternator and the other post from the regulator to the other field of the alternator.
Preferably a 12V source like from a key switch circuit that triggers a relay
I fixed mine with an OEM regulator and a relay that connects a wire straight from the battery to the "I" terminal of the regulator. The relay is energized by the original ignition wire from the key switch.
The "I" terminal senses what the voltage is on the battery to determine how much field current to send to the alternator. I cannot stress this enough, the VR MUST have a good ground. I ran another wire direct from the battery ground to the VR. Only now does the charging voltage set right. This eliminated the pulsing in the headlights at idle also.
The VR's that I got from O'Reilly's are junk. One set the charge at 19 volts and cooked the battery and the others set the wrong voltage or didn't charge at all. My alternator has never been touched.
I fixed mine with an OEM regulator and a relay that connects a wire straight from the battery to the "I" terminal of the regulator. The relay is energized by the original ignition wire from the key switch.
The "I" terminal senses what the voltage is on the battery to determine how much field current to send to the alternator. I cannot stress this enough, the VR MUST have a good ground. I ran another wire direct from the battery ground to the VR. Only now does the charging voltage set right. This eliminated the pulsing in the headlights at idle also.
The VR's that I got from O'Reilly's are junk. One set the charge at 19 volts and cooked the battery and the others set the wrong voltage or didn't charge at all. My alternator has never been touched.
Edwin
Could you possibly write a schematic if how you have this wired? Thank you!
I understand the stick to a point. Mine doesn’t have a oem regulator that came with it (it’s a 92) so I’m a bit confused on how I would wire up the relay with having different wires
I understand the stick to a point. Mine doesn’t have a oem regulator that came with it (it’s a 92) so I’m a bit confused on how I would wire up the relay with having different wires
I think you can adapt the newer models with the old style VR but you'd need more expert than I have between my ears right now. Hopefully somebody else will chime in.
If you get the reference voltage for the regulator from the ignition switch, it'll be low, and the regulator will then run too high. This truck run's all kinds of junk through the ignition switch, so things like the heater motor would make the regulator change the alternator voltage. Reference should be a direct wire to the battery through a relay. Drive the relay with the wire from the ignition switch. 12V to the alternator should be a separate circuit. Stock gets it from the ASD relay. That would be fine.
You can build a new VR circuit with a 4 pin relay sold at any autoparts store using any 12V key on source as your trigger. Keep your feed line from the alternator to the battery if you don't feel like spending the extra money on 6 gauge wire.
You said you added an external VR. How do you have it wired?
08-16-2019, 04:01 PM
