2002 F250 Alternator Problem
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2002 F250 Alternator Problem
I have a 2002 F250 7.3 Power Stroke that seems to be eating alternators. It has gone through 3 alternators and today I think it got another one. It started fine this morning no problems running or starting then went out tonight to start it and not even a light came on. What could be causing it to burn up alternators, (last one only lasted 2 months, one before that lasted 6 months)? Any ideas would be appreciated.
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
If you still have the original battery, go ahead and replace it for good measure. You didn't say if it was electrical or a mechanical failure. If it's eating up or cooking the bearings, or if it slowly reduces output voltage or one day just stops putting out at all.
I recently went through the same trouble, I bought a $700 high amp alt, did a big three upgrade and it turnout I had a cell dieing in the battery. Finally I caught a break when the battery would not take and hold a 13.2v charge.
I recently went through the same trouble, I bought a $700 high amp alt, did a big three upgrade and it turnout I had a cell dieing in the battery. Finally I caught a break when the battery would not take and hold a 13.2v charge.
Post Fiend
Joined: Jun 2004
Posts: 9,293
Likes: 10
From: Parker, CO
Bad batteries can kill the alternators in our trucks. Load testing the batteries means you need to disconnect them and test them one at a time. If you test them both while they are still hooked up, you can get a false reading.
Good luck
Good luck
Postmaster
Joined: Apr 2005
Posts: 2,759
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From: round rock, tx
same with my 02 as well
I have owned my truck since 2005 and have gone through at least 3!
There is a problem with the two wire pigtail that loses contact with the onboard voltage regulator(6G) Go to any auto parts store and buy the $30 replacement pigtail. cut off old one and splice in new one, making sure to solder and heat shrink connections. The replacement unit will have three wire, middle one is not used. I have since added a additional ground wire at starter to frame. I think our trucks have a plethora of electrical gremlins!!
I have owned my truck since 2005 and have gone through at least 3!
There is a problem with the two wire pigtail that loses contact with the onboard voltage regulator(6G) Go to any auto parts store and buy the $30 replacement pigtail. cut off old one and splice in new one, making sure to solder and heat shrink connections. The replacement unit will have three wire, middle one is not used. I have since added a additional ground wire at starter to frame. I think our trucks have a plethora of electrical gremlins!!
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Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
The alternator is grounded to the engine block and starter. Then the engine has a wire going to the body. Then a wire from the body to the neg batt terminal. Replacing the wires (engine to body), (body to neg batt term) and then the charge wire (alt pos to batt. pos) is what the big three upgrade is. 4ga is about as small as you want to use for the upgrade, bigger is better but wasted if you haven't upgraded the charging system.
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