Dead battery question

[barry]

'83 3/4 ton with 6.2
has new batteries, new alt, new starter, all cables are new except for one ground cable. volt meter seemed to be low last night(never noticed if it worked right anyway), slow to crank this morning but it did. Had to jump start it after work, won't start right after i turned it off. I had 2 new batteries and put in. It started right up. didn't have time to investigate yet, can't find volt meter right now. I have to got to harbor freight and get a volt meter, cheap but they work for $4)
What would you check?
I don't want to drive it in case it is the alt, the 2 batteries SHOULD give me 20 minutes drive time to get to my plow truck(right?) calling for snow tomorrow.

 

[towcat]

barry-
you have a short in the system somewhere. even when you're not running the batts are being discharged. if I was in your situation and snow is coming, I'd charge up the batts and leave them disconnected when not driving. Its a PITA with GM side terminals, but until you have a chance to run down the short, and you need the truck, that's the best suggestion.

 

[barry]

I put another alt. in it and it was putting out enough volts. The original (rebuilt) alt wasn't putting out enough volts. It tested fine at one store and bad at another. Truck has been fine for 2 weeks, went to start it this morning and it wouldn't start. I did some tests and it did not appear as though there was a draw on the batteries with the truck off. My drivers door wasn't closed all the way, but the interior light doesn't come on with the door open anyway. I don't know *** is going on.

 

[robert wyrick]

Check the starter. I had the same problem. When running the lights would dim badly. but when you checked the alternator it would be okay. slow to no start sometimes. found that the wires to the starter had become exposed and were rubbing the frame. fixed that and the problem is no more. Good luck to you.