Why does my Alt hum? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Russell · 08-27-2005, 01:42 AM

Hey all!

I've got a newer style alternator in my truck, as it has serpentine now. I have it hooked up as follows: Thick wire is hooked up to the big post, which goes straight down to the battery, thin voltage sensing wire is hooked up to the old red wire, and the brown idiot light wire is hooked up to the old brown wire through a 75 ohm resistor as I was told to do. The alternator charges like it should when the engine runs (14.9 volts on the nose) but when it is just sitting there, the alternator makes a noticeably loud humming noise. Anyone have any ideas what it could be?

08-27-2005, 01:42 AM	#1
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Why does my Alt hum? Hey all! I've got a newer style alternator in my truck, as it has serpentine now. I have it hooked up as follows: Thick wire is hooked up to the big post, which goes straight down to the battery, thin voltage sensing wire is hooked up to the old red wire, and the brown idiot light wire is hooked up to the old brown wire through a 75 ohm resistor as I was told to do. The alternator charges like it should when the engine runs (14.9 volts on the nose) but when it is just sitting there, the alternator makes a noticeably loud humming noise. Anyone have any ideas what it could be? __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.