ok i have a 95 xj and some weird crap started to happen. I was out 4x4in and noticed that my voltage gadge had dropped below norm. so i started to drive back to the house thinking the alt died on me. the next thing i know the dash stops working like nothing works no speedo no tach nothing then the engine dies so i get my buddy to grab an extra battery so i can limp the thing home. i put the new batt into the jeep and it runs and the dash works agian but the altinor is still showing nothing on the dash. so i replace the alt with a new one that i know works. and have a new battery. the thing is ITS STILL NOT CHARGING THE BATTERY. even though everything is connected and i got the alt tested and it works fine. im stumped. im thinking it could be the voltage regualtor but im pretty sure thats inside the alt. can someone tell me wtf is going on please.

 

could the ecu/pcm have anything to do with the charging system?

 

The voltage regulator is inside the pcm, it controls the "feild" of the alt. On the two small wires on the back of the alt the green/orange should have 12v running(light a test light) the other wire green (i think) should light a test light as well, this wire is the one that the pcm pulses to ground to make the alt work, momentarily ground this wire and see if the alt will charge.
Youcould wire up an external voltage reg, or install an internally reg alt but you will have a check engine lamp.
good luck!

 

i have heard of guage clusters doing that. best bet is to put a aftermarket volt meter in to double check your guage on the dash. sometimes the guages will stop working and then just start working again thats a sign your cluster might be going bad