What do the wire colors on alternator wire harness mean?

Tiny
KING8657
  • MEMBER
  • 1988 HONDA PRELUDE
  • 240,000 MILES
Took my jdm 3 pin alt plug off harness and spliced a 4 wire usdm(i think) plug to harness. Wire colors on my harness are black/yellow. Blue/white. And green/white. Those wires match up so I spliced those to the plug, but there is extra red/white wire hangin. What do I do with it? What do the colors mean and what is their function? I didnt have the money to buy an oem alt from parts store so im trying to work with what I got?
Saturday, May 19th, 2012 AT 4:09 AM

7 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
It goes back to the computer-see below
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Saturday, May 19th, 2012 AT 5:23 AM
Tiny
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So on my carbed prelude will this alternator work? If so then where should I connect or splice the extra red/white wire to make it work? Should I just leave it hanging?
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Saturday, May 19th, 2012 AT 9:07 AM
Tiny
RASMATAZ
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You can ignore it-and check the running voltage of the alternator if its correct
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Saturday, May 19th, 2012 AT 4:53 PM
Tiny
KING8657
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On my other post about this problem they said it wont work. So will the fi alt still work on my carb prelude?
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Saturday, May 19th, 2012 AT 11:41 PM
Tiny
RASMATAZ
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The wire you refering to goes back to the computer as indicated in the picture which controls the alternator's field generation circuit-
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Saturday, May 19th, 2012 AT 11:47 PM
Tiny
KING8657
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So will it work without that wire plugged into anything
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Saturday, May 19th, 2012 AT 11:50 PM
Tiny
MHPAUTOS
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As mentioned in the earlier question, it will not work as designed, I feel that it will do one of two things, not work at all or go to an over charge state, which can do serious damage to electrical systems, the colour coding is just to distinguish which wire goes where on the schematic, I would suggest that you get your old alt overhauled and avoid the possibility of doing any damage.
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Sunday, May 20th, 2012 AT 12:13 AM

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