medicmike5969

I have been trying to figure out why I intermittently have low alternator output on my '05 Suburban w/ 5.3L V8. Sometimes (& especially when I need it) the voltmeter will drop down to about 10 volts while I'm driving or just sitting still. I know that the voltage module (located on the Negative battery cable near the battery) is supposed to sense the need to more amperage from the alternator depending on the electrical load - but either it's not doing it, OR the alternator isn't kicking in (been bench tested 3 times & checks good) OR something with the PCM?

I tried a trick that one of the head mechanics for one of the Ambulance Companies that I used to work for told me about - that he had to do with the Chevy Ambulances (he found this out from Chevy somehow) & that was to run a separate wire from the alternator down to the Voltage module. That didn't help.

I replaced the voltage module - that didn't help.

Battery has been replaced - That did help some. It doesn't drop on the charging as much as it did before.

I also did swap out a different alternator - no difference.

I'm at a loss on this & it's a pain in the butt when I'm travelling & the inverter won't work because of too low of voltage coming into it.

Hopefully someone can point me in the right direction?

Mike