alternator problem 1994 grd cherk lrdo

[ranchos]

afternoon everyone, 1994 grand check lrdo, battery new, alternator tested off vehicle puting out @ 15 volts, however when place back on gcl, with a small black box that attaches to two small poles on top of alternator is connected, the voltage drops to @ 12.4 and the amp guage in dash does not go past 1/4. so i assume this black box is voltage regulator or some other part, since 1994 the voltage regulator is external, kragen doesn't show this part, if it is to be replaced, i'm not sure what part am i looking for, budget is holding me from dealer, any body have any direction, this is my daughter college transportation, is this something i can fix, so far i diagnosed to this point???----help

 

[SteelHeadz]

Welcome to Jeepz. The voltage is regulated by the PCM. Check the battery temp. sensor located under the battery first. It's a round black flat sensor that makes contact to the bottom of the battery .If and when this sensor fails, it will give the PCM a false temperature and would either overcharge or not charge the battery at all.