did you ever figure this out i am havingt he same problem

 

i have a feeling my battery is getting drained out by something. i dont know what is doing it yet, but that seems to be my problem. when my truck is running the voltage just starts dropping down to 10 volts before the engine starts to die out. then when its off the voltage slowly goes back up to 12 volts. but even the 12 volts wont start it unless is hooked up to another vehicle and then the 13 volts the other vehicle is putting out will start it.

 

well guys we got ours fixed i was looking at another post on marlincrawler.com turns out the autopart store gave us the alt for the 6 wire external regulator where ours was a 5 wire took ti back and got the right all alt. and now it charges. the charge light doesn't work (wouldn;t go out tried another lamp relay then it wouldn;t come on but it read 14.5 volts at the battery so i think we are good for now!. funy part was the alt we had had a green plug on ti and the wires still plugged into it


tought i would share with you guys maybe it will help you guys out!

 

cool! congrats on the fix.

when i got my alternator, i got one for a 1980. the door jam plate says it was made in december of 1979. is my truck a 79 or 80? i read somewhere that it should be an 80 because it was made at the end of the year of 79. would it even make a difference even thought the plugs matched up?

 

yes the plugs matched up on both of the ones we had. if you have a 5 wire external regualtor u need the alt with a black plug on the back of the alt. http://shop.advanceautoparts.com/web...S_539239512___ if you have a 6 wire external regualtor you need the alt witht he green plug on the back http://shop.advanceautoparts.com/web...S_539227315___


like i said we had the one with the green plug where we need the one with the black on my friends 83

here is another great site http://home.earthlink.net/~twopapa/bigalt.htm