ok.. so heres the deal. IT DOESN"T WORK!!! jk both batteries test good SOMETIMES the chraging system says its charging, i can be going down the highway and it wont be working then all a sudden it will go on, just whenever it feels the urgehttp://www.dieselplace.com/forum/smileys/Angry.gif. could it be a short somewhere? i just put in a new alternator and it worked for a few minutes then started doing the same efn thing.

I would get a voltmeter and do some troubleshooting. The voltage regulator is internal to the alternator so there could be a short or groud that is causing the voltage regulator to not operate correctly

Just a shot in the dark, check your battery terminal connections. My dad's 6.5 was doing the same thing not too long ago, ended up towing him home with my '03 duramax. He went through 3 altenators and still dying on him. He finally took some contact cleaner to the terminals and cable ends and hasn't had a problem since.


-Zorganov

GNDs notoriously bad on GM trucks, check to see that bonding straps between engine and frame are clean & intact, I had crappy charging on my 90 gasser when strap on back side of engine by starter broke.


if you have the under hood lite option or cab lite and door open; at nite, touch a wire from the block to the frame and see if it gets brighter, if so probably a bad gnd. to remidy I hooked a #4 batt cable to back of alt bracket and a bolt on the frame claamping one of the hose clamps, my charging and premature alternator/batt death problems cured.