External voltage regulator

[jesnic]

I have installed three seperate alternators and each one has been no good. The Gauge would drop to 8 volts after while and the alternator would not charge. Came up with codes 1682, 0622,0500,1765,1693, 0501. Figured it was the pcm. So I installed the external regulator and bypassed the pcm. Cut the wires on the alternator, wired up the ext VR, checked all the grounds, installed new battery connections and now the new alternator is charging at 14.7 - 15 volts, measured at batteries and reads the same on my scan gaugeII. But after few minutes the gauge in the trucks ramps up to 18 volts and check gauges light comes on and stays that way. The voltage at the batteries is still 14.7 - 15 volts. Any one have any ideas on what is happening?

 

[tractorguyacb]

PCM most likely sees lack of control then throws over voltage. Just go get a reman PCM they are not that expensive at all.. or pull the check gauges bulb and run it.