Alternator testing?
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Elder User
Joined: Feb 2004
Posts: 772
Likes: 3
From: Mount Airy, MD
Alternator testing?
Short of removing it and having it bench tested is there an in-vehicle test that I can do to check the output voltage?
Also, if I end up having to replace it, does anyone have any suggestions for a replacement? Aftermarket or OEM?
Also, if I end up having to replace it, does anyone have any suggestions for a replacement? Aftermarket or OEM?
Senior User
Joined: Jul 2006
Posts: 206
Likes: 0
Go to Radio Shack and buy an inexpensive DMM (Digital Multi-Meter).
If you have a Diesel, your battery voltage should be about 13.8 right after you start the engine.... after the glow plug relay drops out, you should have about 14.5 V. If you have a gasser, it should be 14.5 V right away.
If you have a Diesel, your battery voltage should be about 13.8 right after you start the engine.... after the glow plug relay drops out, you should have about 14.5 V. If you have a gasser, it should be 14.5 V right away.
Post Fiend
Joined: Dec 2002
Posts: 6,245
Likes: 1
From: IL, USA
Yep, also they make cheap Battery/Alternator Testers as well for under $20
But a Digital Multi-meter is nice to have as well.
Snap on and other tool companies make batt/alt testers that allow you to load test it as well.
But a Digital Multi-meter is nice to have as well.
Snap on and other tool companies make batt/alt testers that allow you to load test it as well.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
A quicky test just to make sure it works:
With engine running turn on the interior lights. As you're looking at the light, turn the key off. If the light dims, the alternator was charging. If it doesn't change, or gets BRIGHTER, you have a problem
With engine running turn on the interior lights. As you're looking at the light, turn the key off. If the light dims, the alternator was charging. If it doesn't change, or gets BRIGHTER, you have a problem
Senior User
Joined: Dec 2005
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FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
The simple "watch the light" test will tell you if it's charging.
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