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Kal061506 · 03-09-2008, 04:43 PM

I have 1981 GMC with a 305 voltage indicator shows decharging when the blower motor slows down then goes back up to charging when the blower motor speeds up. thought it was the fan motor but I replaced it and it still slows down and speeds up and the voltage drops when the fan slows down I had the alternator checked and the tests said it was good new battery clean posts good grounds Iam at a loss to why the fan motor slows down and the charging stops until the "load comes Off " could the alternator be no good even if a check on the alternator says it is ?

03-09-2008, 04:43 PM	#1 (permalink)
Kal061506 Registered User Join Date: Mar 2008 Posts: 1 OS: XP	blower motor causing decharge on and off I have 1981 GMC with a 305 voltage indicator shows decharging when the blower motor slows down then goes back up to charging when the blower motor speeds up. thought it was the fan motor but I replaced it and it still slows down and speeds up and the voltage drops when the fan slows down I had the alternator checked and the tests said it was good new battery clean posts good grounds Iam at a loss to why the fan motor slows down and the charging stops until the "load comes Off " could the alternator be no good even if a check on the alternator says it is ?