I have a 99 chevey S10 blazer 4.3 vortec.. I am having issues with my voltage meter bouncing when I am stopped or in park. While in driving it stays at 14 but once I stop and put it in park and allow it to idle it bounces between 9 and 14.. It hasn't home down to 9 since I have replaced the ignition coil, ignition control module, MAP sensor. But its still bouncing and I don't like it... Please help.. I've had battery and altentor tested while on vechiel and I'm told that they are fine..

 

If your voltage regulator connector on the alternator has one red wire, the problem is in the alternator. It is not always detected by conventional testers and test procedures. It requires more complicated test equipment, (oscilloscope) and an experienced technician to diagnose it.


If the regulator connector on the alternator has 3 wires, this will fix the problem. https://blazerforum.com/forum/tech-a...ference-60425/