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#1 |
Registered User
Join Date: Dec 2010
Location: Calgary
Posts: 2
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Electrical Problem
I jump started my 1969 GMC Pick-up but accidentally reversed the polarity when jumping. Now all the lights flicker when the truck is running. I relpaced the alternator c/w it's internal voltage regulator, battery and flasher relays and the problem still persists. Any ideas on what to try next?
Thanks, Orange 920 |
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#2 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: Electrical Problem
is the light switch on when this happens?
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71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#3 |
Registered User
Join Date: Dec 2010
Location: Calgary
Posts: 2
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Re: Electrical Problem
Yes the light switch is on.
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#4 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: Electrical Problem
i'd start by removing both battery cables and clean up all 4ends and where they mount to bright and shiny then reinstall the cables and see if that helps
__________________
71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#5 |
Registered User
Join Date: Aug 2009
Location: St. Paul MN.
Posts: 1,996
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Re: Electrical Problem
Make sure the alternator belt is tight and put a volt meter on the battery positive on the back of the alternator and to a good ground, if the voltage jumps around like your lights, go get another alternator.
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Fuzzy |
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#6 |
Msgt USAF Ret
![]() ![]() Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,714
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Re: Electrical Problem
I think there is a possibility that you have blown one of the diodes in the alternator bridge rectifier. The large red wire on the back of the alternator comes directly from the battery and connects to this bridge ( see diagram).
When the polarity was reversed it may have caused the diode to blow which would have dropped the dc output to the large red wire circuit. It's also possible that one of the diode trio diodes has gone which would reduce alternator output. I would check the alternator output with a voltmeter between the large red wire on the back and the best ground handy. If the meter flickers it indicates that output is rising and falling. do this at steady rpms of course. You might also unplug the small plug on the top of the alternator and check the lights for flickering. This makes the alternator output go to zero and if the flickering stops that eliminates a poor connection on the light wiring circuits. Do this with the engine off to avoid residual magnetism in the alternator field from outputting voltage to the system. My first thought was the same as yours, that it was the regulator. What is c/w that you say you changed? notice that the large red wire goes directly to the bridge rectifier
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VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. Last edited by VetteVet; 12-12-2010 at 12:34 AM. Reason: forgot diagram |
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