Voltage regulator

paddywagon

New member
It appears that the voltage regulator is part of the pcm...really? not one of chryslers brightest ideas...Is this serviceable? or do I need to replace the pcm? I'm reading battery voltage from the alternator through the pcm and at the volt gage on the dash. Alternator is good (according to the machine at the autoparts store)...

If I have to replace the PCM, willI need to reflash it, or is it old enough to be a plug and go?
 

What year and model Jeep do you have?. Most of the older PCM is a plug and play depending on the year it was built. For the most part, the VIN and odometer needs to be programmed into the new PCM on the cherokees and grand cherokees.
 
sorry, its a 91, plug and play...pulled the pcm out and took it apart, appears to be part of the mother board...Really? did chrysler think that they would never go bad?
 

Option 1: Get a single wire alternator, swap the serp. pulley Napa has them for under 100 bucks. 213-4011sw (stands for single wire) Great option in any build, farmers use them forever.

Option2: Go to Napa and buy a VR38 or VR38SB (cheaper) This is a chrysler external voltage regulator. Pretty simple to wire up, there should be a diagram in the box. To make it beautiful buy the VRC38 (factor connector) this will make it easy to wire up and keep mud out.

You will have to put electrical tape over the idiot light
 
I finally got the pcm today, replaced it and still have the same problem. I read battery voltage all the way from the battery through the alternator and to the gauge. Am I missing something?
 

nope, not charging. I have the same voltage at the battery, alternator, and the gauge on the dash.
 
all fuses and relays are good. gonna do a little more checking and may wind up just wireing in an external voltage regulator. not the way I wanted to fix the issue but i cant keep waiting around for shipping times.
 
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