I've searched, a lot, but couldn't really find a definite answer. Do I have an external or internal voltage regulator on my 87 cherokee. Bc I have this voltage surge that either causes my voltage to show really high or drop so low it dies while driving. Thanks for any information regarding in my problem.

 

1987 gasoline engines have a Delco CS-series with internal regulator.

(Diesels have a Paris-Rhone, I don't recall where the regulator is.)

Bear in mind that the RENIX IP voltmeter is a notorious liar - any suspect readings at that gage should be verified using an independent DMM!

 

Paris-Rhone is internal, part of the brush holder assembly.

 

Can the gauge it self be replaced with a 91 and up gauge not cluster just gauge i wonder?

 

I hear the too about the gauge going bad. But I think mine is fine bc when it reads low, the lights dim and it has died twice.

 

I don't think it's so much the gage itself going bad, but I don't know where it picks up its voltage signal.

I just use it as a "relative state-of-charge indicator" - get out your grease pencil, confirm a good voltage reading with a DMM, and mark the lense. When it's off the mark, then recheck.

I don't care what year the vehicle was made or who made it - the first thing I do when I get a suspect gage reading is verify it! The gage could be lying through its teeth to you...

 

According to the IP drawing, on the '87 the voltmeter taps into the positive cluster supply, also used to power the fuel, oil pressure, tach and temp gauges. All are fed through fuse # 17, which also powers the headlamp delay and warning chimes.
The negative side of the gauge shares the IP cluster ground. Any sort of fault in the fuel, oil pressure, tach or temp gauges will probably drag the voltmeter reading down.