Does anyone know if a 1992 cherokee 4.0L, alternator is regulated by the ECU or is it built in the alternator?

 

Don't make me swear to it but I think the internal altenator thing started with the '96 models.

 

Should anyone else have this problem, after 2 days of searching thru wiring harnesses for a blown fusible link( this is what the chilton manual says to do if during the power test ie: remove wiring harness from alt. check with a test light for power thru the harness with the key in the on position. If the light does not come on you have a blown fusible link in the harness). Most test lights require close to 12V to light. If as on my cherokee the regulator is in the PCM, it only puts out about 7V, not enough to light up a test light. When I checked the output to the harness with a voltmeter, I discovered it indeed did have power, 7V. The alternator itself is the culprit. I changed the alternator 8 months ago, and since Chiltons test said there must be power thru the alt. harness, I assumed the problem was not the alt. itself. Case in point, use meters instead of test lights whenever possible.

 

Good point. I almost always use the meter b/c I keep blowing the darned bulbs in my test light. I have a test light but would rather see a needle move or numbers register on a screen.

 

I don't even own a test light i only use my digital multimeter

 

What's a test light??

 

I've got both..test light and meter. When I am looking for a hot and can't find the end, a test light is a quick way to see IF you have power. Sometimes for fast testing, its easier to clip the ground and probe the wire, then try to play 3 handed drop with a wire and two leads.