Hey folks! I have a 2001 ram 1500 We had a snow storm recently and after the storm I started my truck and it was not charging it was at 8 volts (running) but if I just put the key on it shows 12v, I took a drive yesterday and the truck was charging just fine and all of a sudden the gauge just went right down to 8v and the belt started squeeling like it was trying to charge heavy but I was only seeing 8v, what I dont understand is when the alternator "quits" shouldn't I still see 12v battery power on my gauge? And if the alternator was working hard to charge "why else would the belt squeel" there should be voltage on my dash should there not? Also it seems to act up right after a shift (truck is manual) so when the rpms go down when I shift thats when it does it, also if I leave the heater off it doesn't seem to do it but If I put the heater to 3rd gear or higher then I make a shift it seems to do it? What could this be? I just find it odd that the voltage will drop right down but the belt will squeal badly, I haven't had the chance to poke around with a multimeter yet to see what's going on since it's so cold and dark when I get home but I'm thinking the problem is not the battery or the alternator, any help would be appreciated thanks!

 

There is a fair bit of draw on the system with the engine running, and the volt gauge ain't the most accurate in the world. Given your symptoms, think I would take the belt off, and spin the alternator by hand. See if it feels crunchy.

 

The tensioners on these trucks get flakey, make sure it's working well.

I think you've got either a failing tensioner or alternator, but do some digging before throwing parts at it.

 

Thanks for both of your input ill deffenitly check the alternator and the tensioner but would the belt slipping make me see no volts at the dash seems to me I should still see 12v on the gauge?

 

The alt is controlled by the PCM. Now, I don't know how the voltmeter gets its reading exactly but I don't think it's as simple as two wires straight to the battery. Point being, if the alt were flakey I could see the PCM not knowing what's going on and giving no reading.

I do agree that a slipping belt wouldn't cause the gauge to read nothing.....but a noisy belt at the same time the gauge goes weird could obviously suggest a connection like the alt is trying to lock up

 

I suspect bad bearings in the alternator, and the belt squealing is the alternator trying to lock up.

 

The voltmeter on the later trucks is controlled by messages from the PCM and does not reflect a true analog reading. More specifically any voltage under 10.8V makes the needle go all the way down to the 8 mark and if the voltage comes back up above it the needle jumps back up as well.

 

Thats actually really good to know and also i beilive the other 2 were right about the tensioner we had a really mild day with some rain and since then the truck has been working good hasent dropped below 14 so I'd say the tensioner was frozen, here's to hoping!