It's a 99 c3500. I know what drained the batters down and have fixed that. Its just that it sits for days and cranks rite up. No sine of bad battery sells! When I found them dead. I put the trickle charger on the for at least eight houres then removed the charger befour cranking it. I do have a...
Thanks for the response! Good point but the volt gauge is running just a little below 14 volts? Can just the part in the alt that runs the tach be bad and not the charging part?
So the other morning I go out and the batters where dead! Nothing I mean dead. I put the charger on them and found the problem (bad door switch) no problem. Now the tach is way off! Idling at 1800rpm and cruising on road at 60 the its over 4 k? Any ideas?