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97 GMC YUKON lights flickering
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Guest
Anonymous Poster
snoe2006@yahoo.com
Apr 24, 2008, 4:12 AM
Post #1 of 6
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97 GMC YUKON lights flickering
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My friend has a problem with headlights flickering. He purchased a new alternator, and I checked his battery which is good . I thought maybe it is a short in the charging system, but I'm noy exactly sure. Can someone point me in the right direction ? Thanks very much
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 24, 2008, 4:34 AM
Post #2 of 6
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Re: 97 GMC YUKON lights flickering
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Questions + suggestions: Did this do this before this new alternator?
Are the lights just dimmer and brighter or really going off and on?
I'd take a voltage reading while it does this and would blame the alternator new or not for the moment depending on just what you find,
T
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willyg
User
Apr 24, 2008, 4:46 AM
Post #3 of 6
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Re: 97 GMC YUKON lights flickering
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I do know that the lights just get dimmer and brighter, but I will get the other information about the alternator and get back to you. Thanks
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willyg
User
Apr 24, 2008, 5:12 AM
Post #4 of 6
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Re: 97 GMC YUKON lights flickering
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You said take a voltage reading, what specifically am I checking? and one other thing I did notice that his battery cables don't appear to be in very good shape. Could this be one of the problems? Thanks
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willyg
User
Apr 24, 2008, 1:30 PM
Post #5 of 6
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Re: 97 GMC YUKON lights flickering
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One more thing a trouble code po121 came up on my scanner. We replaced the tps, and now it shows po122. What did I do wrong?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Apr 24, 2008, 5:44 PM
Post #6 of 6
(2570 views)
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Re: 97 GMC YUKON lights flickering
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If you see problems with the battery cables then certainly clean those up or replace as needed. Lights are senstive to the voltage they get. With engine off lights are getting about the 12 volts that the system is called but when engine is running the voltage will be at alternator output which is a range of about 13.5 to 14.5 and they look brighter and stay that way. If the alternator quits putting out voltage intermittently it very well could and would be seen as dimming and then a brightening of lights. Just taking voltage at the battery - engine running and watching the headlights and the voltage reading would show if it's steady or jumping up and down with an intermittent problem.
This is just a start to the possibilities. You need to know the cables and any seen problems with connections are ok first. That alone could be the trouble so check and or clean them all - both ends of both battery cables,
T
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