Originally Posted by 88dually
wife started car, battery light came on, after market volt gauge said 12. after running a few seconds, lite went out an gauge went to 14. Does that light mean alt is going bad ?
Could be a loose connection somewhere.
The alternator does not have a built in regulator but is controlled externally by the PCM....make sure the two-pin plug and the large cable on the alternator are on clean and tight and maybe disconnect the battery and re-plug the PCM connectors a few times to clean them up.
Bear in mind that the early KJs have a Battery Temperature Sensor located under the battery...senses battery temperature so that the PCM can accordingly adjust the charging rate.....any problem with this sensor also lights up the same battery light on the console that a charging issue will light up...I had this battery temperature sensor issue.
If you can pull codes you will see if it is a charging issue or a Bat temp sensor issue.....if the problem comes back then let us know and I will give you some pointers on what to do!