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Old 01-16-2010, 07:27 PM   #11
Still on 3 wheels
bmwhacker's Avatar
Joined: May 2009
Oddometer: 4,495
Originally Posted by bpeckm

Above are the table of how to match the color wires plus the "pin" number to be able to test whether this will work with your harness. Note that the pins seem to be common to both my /6 and 1981-vintage wiring harnesses. BMW has used a common color/wiring system (which actually is a common Euro-designated color scheme) which you should be able to transpose as necessary to the different airhead wiring harnesses (harnii? ...)

I guess one cannot cut and paste a Word document, so I scanned and saved as a .jpg. Hopefully you will be able to "steal" the photo in a large enough format to be able to save it and read it.

Feel free to PM me with your email address and I will gladly email you the Wrod document in ".doc" format.

NOTE: As noted in the scanned document, the little triangle (gen warning light) does not work, due to the different way that BMW uses the gen-light as part of the alternator-excitation circuit.

It is hard to explain unless you have been into the wiring and understand the BMW system, but essentially, the gen-light is "on" when the green/black wire has +12vDC (ignition "on", but bike not running) and the blue wire has no power yet. This provides a small current THROUGH the filament that excites the alternator field, and once the engine is running with an excited alternator, the blue wire has "it's own" 12vDC, cancelling out the green/black 12vDC, and the light goes out.... Simple and effective, but there is no way to wire this function into the Acewell since there is no way to get the blue wire to the negative side of the indicator: Acewell uses battery ground as the negative side.

I bypassed this problem, as noted above, by picking up the blue and the black/green from the harness and running the two of them to a separate indicator. That is the red light underneath the Acewell.....below:

It functions as it does on the BMW pod: inition "on" and light comes on, start and blip the engine, and the light goes out. Simple, effective.

I think that, unless someone clever comes up with a way to use the internal gen-light function, I would order the unit without the gen-light, and use the separate indicator, again.

Still, could not be more satisfied with the unit, the way it is built, and the way that it is working.

Mounted my Acewell speedo today and started to sort out my wiring.....sat down with your info and double checked to my 1974 wiring harness....all looks good except that mine was a mechanical tach.....When picking up your "unswitched" clock power (red) which terminal in the headlight pod did you tap to? Your work shown here sure is making my life easier!!!!! I'll buy you a beer or two if we ever cross paths!!!!!!!

Living proof you shouldn't play with matches
ABC# 1992
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