Hey guys I have a 1990 jeep Cherokee limited 4.0 4x4 and I bought it used and put in a new motor ( had one from my other jeep). Well I notice that the alternator gauge dosent read. So I figured bad alternator and since I was buying electric fans and some LEDs I figured just to buy a new 100 amp alternator because i didn't know the condition of the old one. Well long story short I installed the new alternator and my gauge didn't move from the red. I have already refreshed all the grounds according to cruisers54 tips. I have yet to install thicker wire from the alternator to the relay( is that correct the wire from alternator to the actual relay and not battery post +??) and when I turn on my fans lights dim a lot ( it should be a total of about 25 amp draw from the fans together), haven,t checked voltage at battery due to not owning a multi meter, but i heard people disconnecting the positive cabke and if the jeep stays on alternator is good and if its bad turns off ( is that a good test??)

 

Get the multimeter.

 

Even a cheapee digital multi-meter from Harbor Freight will let you know if the battery voltage increases like it should, when the engine is started.....

 

$5.

 

I have. Another post in another section and what I stated there was that I bought a 4 gauge wire and connected that from the alternator straight to the battery post (+) with engine of I had 12.5-12.6 and With engine running 14.3ish with both electric fans on at idle ( I bought a dmm at autozone didn't have time to go to harbor) should I reconnect the cable to the relay or leave it at the battery post?

 

a bit confusing and it's bed time for me.