alternator blues

beleive · Post by **beleive** » Tue Aug 18, 2009 4:52 pm

Third alternator, seems when I rev engine up would usually kick it in(have volt meter gauge hooked up).Three alternator all do same,but now I have no charge.Belt tight,checked for ground problem?need some advice.Thanks

Vincent Waldon · Post by **Vincent Waldon** » Tue Aug 18, 2009 8:46 pm

Most MK2-vintage Bosch alternators need a slight kick to begin the excitation process... it's even mentioned in the owner's manual of my 1986 Jetta.

Typically this is in the 1100-1400 RPM range and completely normal... I hope you haven't gone thru three alternators trying to "fix" this?!

beleive · Post by **beleive** » Tue Aug 18, 2009 8:59 pm

I was aware of that but didnt know it was normal,but all the alternators failed to work even reving the motor up. Take to shops and say get alternator and they work for a while then quit.?

odie · Post by **odie** » Wed Aug 19, 2009 9:26 am

have you had it bench tested at autozone or other parts store?

Diodes? I had a Renault alt that put out partial power but gen light stayed on. it was a bad diode. there are two or three in the alt, but only one was bad, thus low power.

82vdub · Post by **82vdub** » Wed Aug 19, 2009 10:53 am

I have read some posts on here that have had issues with wiring harnasses and shorts, and open circuits etc that have caused alternators to fail. If you have not done a search or five, do some searching for a solution to this and start reading. You may get some other tips and tips and areas to look at other than the alternator.

vixentd · Post by **vixentd** » Sat Aug 22, 2009 9:16 pm

Check the blue wire that runs up underneath the battery to the dash. It is the light for the red battery light that energizes the alternator. If it is broken the alternator will not want to charge.