Author Topic: BSA 1957 C12 ALTERNATOR WIRING  (Read 163 times)

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ALISON

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BSA 1957 C12 ALTERNATOR WIRING
« on: 13 November, 2023, 12:16:36 »
 Can anybody help with this.
I have a genuine C12 new wiring harness. The colour codes for the wiring to the alternator as per c12 wiring diagram are DARK GREEN/ LIGHT GREEN AND PURPLE.
However my alternator output wiring colours match the alternator for a C15 and are  GREEN/black stripe.  GREEN/yellow stripe and WHITE/with a green strip.
 Can anyone assist  with connecting  the alternator wires fitted to the  correct wiring harness colours.
Thanks in advance

JABBA99

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Re: BSA 1957 C12 ALTERNATOR WIRING
« Reply #1 on: 13 November, 2023, 19:00:30 »
On the "C15" wiring ... White / Green is "common" ... Green/Black is "Charging" and Green/Yellow is "Boost" (when lights on)

For the C12 wiring ... Light Green is "Common" .... Dark Green is "charging" and "purple" (or should that be Mid green or green/yellow ... depending when RM13 was made) is "boost"  .... On service sheet 808D, for C12, "purple" is the -ve output of the rectifier.  Picture from 1966 Lucas manual attached.

The "Common" and "charging" go to the rectifier and "boost" to the switch (so it connects when the lights are on).