Electrical problem... Any ideas? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

redz 1970 K5 · 10-06-2004, 01:37 PM

I am troubleshooting- not sure if my alternator or voltage regulator is bad- both are almost brand new. I am taking the alternator in for test at the Autozone, but I don't want to pay $43 to find out it isn't the regulator.

When my truck is running, the alternator gets VERY hot and begins to whine and smell like it is about to catch on fire; as soon as I disconnect the regulator, it cools down.

This thing ran perfect for a few months before. The wires all appear to be intact from the alternator to the regulator. The regulator is grounded properly.

THanks!

Any help would be appreciated!

BobbyK · 10-06-2004, 02:07 PM

Do you have a volt meter you could take a few readings with?
See what the voltage is at the battery as well as at the back of the alt.You should get about 13-13.8v at the back of the alt and about the same at the battery(with eng. running)
Normally the back of the alt does get hot but it shouldn't "whine".
Do you have a amp gauge in the truck?What is it reading?Is it reading that it is charging or dischargeing?

redz 1970 K5 · 10-06-2004, 04:21 PM

The ahmeter isn't hooked up...

I will check the voltages like you said. Based on what I am seeing (and smelling) I am assuming it may be overcharging so I would expect to see a higher output of the alternator.

Old Dave · 10-06-2004, 05:03 PM

BobbyK is right about checking it with a voltmeter but the voltage can go up to 14.5VDC when at fast idle or running down the road. Any higher than this and it's going to start toasting things. I bet your voltage regulator is stuck and it's causing the alternator to charge at a high rate since the back of the alternator is hot and it smells. This will cook your battery in a short time so beware. Have the alternator checked and if it's OK then chances are it's time for a new voltage regulator.

10-06-2004, 01:37 PM	#1
redz 1970 K5 OBS guy Join Date: Jun 2004 Location: SoCal Posts: 1,060	Electrical problem... Any ideas? I am troubleshooting- not sure if my alternator or voltage regulator is bad- both are almost brand new. I am taking the alternator in for test at the Autozone, but I don't want to pay $43 to find out it isn't the regulator. When my truck is running, the alternator gets VERY hot and begins to whine and smell like it is about to catch on fire; as soon as I disconnect the regulator, it cools down. This thing ran perfect for a few months before. The wires all appear to be intact from the alternator to the regulator. The regulator is grounded properly. THanks! Any help would be appreciated! __________________ 88 Suburban Goodies- Alpine, Auto Meter, BDS, Bilstein, B&M, BFG, Borgeson, Bushwhacker, Cowl hood, Flowmaster, Genuine Gear, Holley, Infinity, JVC, K&N, MB Wheels, MSD, Pioneer, Skyjacker, Sony, Thorley, Walker + more

10-06-2004, 02:07 PM	#2
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Do you have a volt meter you could take a few readings with? See what the voltage is at the battery as well as at the back of the alt.You should get about 13-13.8v at the back of the alt and about the same at the battery(with eng. running) Normally the back of the alt does get hot but it shouldn't "whine". Do you have a amp gauge in the truck?What is it reading?Is it reading that it is charging or dischargeing? __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

10-06-2004, 04:21 PM	#3
redz 1970 K5 OBS guy Join Date: Jun 2004 Location: SoCal Posts: 1,060	The ahmeter isn't hooked up... I will check the voltages like you said. Based on what I am seeing (and smelling) I am assuming it may be overcharging so I would expect to see a higher output of the alternator. __________________ 88 Suburban Goodies- Alpine, Auto Meter, BDS, Bilstein, B&M, BFG, Borgeson, Bushwhacker, Cowl hood, Flowmaster, Genuine Gear, Holley, Infinity, JVC, K&N, MB Wheels, MSD, Pioneer, Skyjacker, Sony, Thorley, Walker + more

10-06-2004, 05:03 PM	#4
Old Dave Is a bullfrog waterproof? Join Date: Nov 2000 Location: OLATHE, KANSAS Posts: 1,130	BobbyK is right about checking it with a voltmeter but the voltage can go up to 14.5VDC when at fast idle or running down the road. Any higher than this and it's going to start toasting things. I bet your voltage regulator is stuck and it's causing the alternator to charge at a high rate since the back of the alternator is hot and it smells. This will cook your battery in a short time so beware. Have the alternator checked and if it's OK then chances are it's time for a new voltage regulator. __________________ "It is better to remain silent and be thought a fool, than to open one's mouth and remove all doubt." Ben Franklin __________________ 1970 Chevy shortbed 2002 Harley Custom Chopper (Long sucker) 1998 K2500 5.7L 5-speed Longbed 1st two are My son's toys...they just live in my garage! 1997 GMC K1500 Suburban 1993 S-10 Blazer 4D (youngest son's daily driver) 2000 Dodge Ram 4WD Ext. Cab (5.9L) Wife is a late year 1951

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