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1998 Blazer ,dashlights pulsing ??

Old Nov 29, 2010 | 05:25 PM
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Default 1998 Blazer ,dashlights pulsing ??

I checked the battery ground its ok, lights in dash and interior are lightly flickering , Alternator and battery checked out
 
Old Nov 29, 2010 | 09:31 PM
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This could be due to the PCM's PWM control of the alternator. I have seen it on a few vehicles. Cleaning the grounds for the PCM & BCM helped, but others had to have the alternator rewired. I believe that someone posted the information on how to rewire the alternator for internal regulation instead of PWM control from the PCM a little bit ago.
 
Old Nov 30, 2010 | 08:26 AM
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What could happen if I dont do anything ?? should I just replace the alternator or pcm ??
 

Last edited by TAZ454; Nov 30, 2010 at 09:36 AM.
Old Nov 30, 2010 | 09:41 AM
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It could eventually get worse to the point of affecting more things. Low voltage situations are not necessarily good for electrical equipment.

I have had a few cases where replacing the alternator did not help the condition so if you alternator tests good, it likely isn't the problem.

The easiest solution is to rewire the alternator to do away with the PWM control.
 
Old Nov 30, 2010 | 09:50 AM
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Is there and thread or site that will explain how to do the rewire ??
 
Old Nov 30, 2010 | 10:00 AM
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I believe there is one. I do not have the time right now to search for you though.
 
Old Nov 30, 2010 | 10:46 AM
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Thanks for your suggestions , your doing a great service for all of us here . Thanks again
 
Old Nov 30, 2010 | 11:32 AM
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mine flicker every once in awhile if im sitting still but i havent had a chance to check alternator yet............
 
Old Dec 2, 2010 | 08:55 AM
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can a positive battery cable that has corrosion on it cause this symptom?
 
Old Dec 2, 2010 | 09:51 AM
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Sure could. I must have mis-read your post as I thought you had checked the battery, but now I see that you just checked the battery ground. Checking the connections to the battery would be a first step for any electrical type problem. Going one step further would be to check the connections at each end of the battery cables (both positive & negative).
 

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