Bad alternator?
Junior User
Joined: Jan 2004
Posts: 87
Likes: 3
From: MN
If you have a volt meter, check what the volts are at the battery with the engine running. The alternator should be charging at darn near 14 volts.
Then check the battery when its not running. It should hold a charge.
When my alternator went, the indicator would come on when accelerating quickly.
Then check the battery when its not running. It should hold a charge.
When my alternator went, the indicator would come on when accelerating quickly.
Postmaster
Joined: Nov 2006
Posts: 4,517
Likes: 3
From: SE Wyoming
Yes, most likely it is a bad alternator. It should read over 14 volts while charging but even when they go bad they can still read good volts. Getting the alternator tested is the best bet, but a lot of the "big box" auto stores have a habit of testing every alternator they see as bad.
Junior User
Joined: Jan 2004
Posts: 87
Likes: 3
From: MN
Wow! I have 180k on my '99 and just replaced my first battery. A good rule of thumb is 5 years though.
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Postmaster
Joined: Nov 2006
Posts: 4,517
Likes: 3
From: SE Wyoming
That many batteries tells me the alternator is weak and eating up the batteries or the batteries were good and the problem was misdiagnosed as a bad battery when it was the alternator. I am only on my 3rd battery now with 240K miles, first one lasted over 6 years and when I replaced my alternator I replaced the second one to be safe.
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Senior User
Joined: Jan 2005
Posts: 435
Likes: 0
From: Pinellas Park, FL
It amazes me the bad luck I guess I have with my truck. 03 5.4 sc 2wd and I am on my 3rd battery and just got a new alternator a few months ago. Truck has 63k mi. It has a couple of tvs (draw hardly any current) and one sub amp. Maybe I need to stop dropping it off to get it fixed and start working on it myself again. I'm sure I could have at least salvaged the battery this last time.Glad you got it fixed though, just had to rant for a minute.
Laughing Gas
Joined: Jan 2006
Posts: 1,098
Likes: 11
From: Minnesota
I am on the original battery that came in the truck in 1998. I have never seen a battery last this long, especially in Minnesota. My truck sits outside in all types of weather. I did change the altenator at about 120,000 miles. I got the "flicker" at higher RPM's. I think I have about 170, 000 miles on the truck. I have always used the OEM block heater when below -0, that makes a huge difference in how it cranks. Glad you got it fixed. It took me 2 or 3 alternators before I got one that did not sound like "turbo whine" when I turned on the lights. There is some real junk on the market these days.
Senior User
Joined: Jan 2005
Posts: 435
Likes: 0
From: Pinellas Park, FL
Spotty - thx for the info. My truck has been back twice because of the whine after they changed the alternator and of they told me it was because of the electronics. Maybe I can get them to replace the altrenator now.
Laughing Gas
Joined: Jan 2006
Posts: 1,098
Likes: 11
From: Minnesota
Yeah... do not accept that. I took back 2 of them to NAPA, they finally gave me a Delco, it is as quiet as the OEM was all those years. They told me it was normal under load for them to whine. I brought the guy out to the truck and had him sit in it. That was all it took. I mean it whined so loud it sounded like I was running a blower set up about 2 feet out of the hood. If they give you any grief have them listen to one that still has the OEM altenator. I'm just sick of junk being marketed as top notch in many situations...Rant over... By the way... Best of Luck...
Jeff
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