Electrical Problem Or Normal?

[hihoslva]

Hello all. I'll keep the long story as short as possible.

 

1999 Suburban C1500, 163,000 miles.

 

Recently, I noticed some voltage drop (by the dash gauge) when using certain accessories (like the blower) at idle. Revving the engine helped, as did shutting off the accessories. At night my lights would dim with the blower on, etc. Figuring my alternator was about to take a crap, I just replaced it. The truck had a the 105 amp alt, but since the swap was bolt-in, I installed the 140 amp CS144 alternator.

 

The wiring harness (single wire but 4-prong harness - go figure) is not the same. My buddy has a '99 with factory 140 amp alt I could use for reference, so I cut my factory harness off, crimped on a connector, insulated it, and plugged the wire on to the same terminal of the alt as his (the middle prong of the three "small" prongs).

 

Truck is running good, and my voltage is 13.75 tested with a multi-meter at the battery terminals. This is with or without accessories running. Is this the correct range?

 

My main concern though is HEAT. The alternator is HOT HOT HOT. I mean burn-your-hand hot after idling for only a few minutes. My 4-gauge fused cable running from the battery to the alt is also quite hot. Not melting, but hotter than I expected.....

 

Is this normal? I don't remember my 105 amp alt getting that hot, but I never really checked it....

 

Should my alt be scalding hot at idle? I'm thinking about a new battery to rule that out, even though it tests at 12 volts solid. My battery is 3 years old (in Arizona heat) and has been fully discharged a couple times. Do I possibly have another issue I should investigate? Is the voltage of 13.75 correct (dash gauge reads between 12 and 13, but the multimeter reads 13.75)?

 

Thanks!

[2COR517]

Battery is suspect. Alternator should not be that hot, especially with no load on it. Battery should read 12.6 volts. Shut the truck off, leave your lights on for a minute, then take a reading. Disconnect the ground cable from the battery and see if it changes.