Alternator wiring - blue wire?

[lkadams]

My car is a bit of a mish-mash (1969 912 converted to a six) so a wiring diagram that fits is non-existent (69 911T is about the closest). I am in the midst of swapping engines to put my rebuilt one back in, and I took really good notes and pictures of all my connections to put it back together (alternator and everything moved from the old engine to the rebuilt). However, as I am double and triple checking everything, past me may have done some things that current me questions. One thing is the wiring from the alternator to voltage regulator.

The thing that mystifies me is that my alternator harness has the big fat B+ wire, the black DF wire, a brown D- wire, a red D+ wire and a blue wire. None of the wiring diagrams I can find for an externally regulated alternator show a blue wire coming from the alternator.

My guess is that the red D+ wire and blue wire come from the same place, and the red wire goes to volt reg and the blue wire is gauge light. The way that everything was hooked up before "worked" - but the red D+ wire was homeless (the blue wire was going to D+ on the volt reg). However, I'd rather not have to pull my alternator out just to confirm. Is anyone familiar with the blue wire coming from the alternator proper?

Thanks for any help!

[30westrob]

Blue wire is D+. It goes from the alternator through the 14 pin plug to the voltage regulator then goes to the charge light in the gauge. Rob

[lkadams]

Thanks Rob - based on your input, I dug a little deeper and pulled up the 1972 diagram which shows that arrangement. I must have found that at some point in the past, because I had mine hooked up according to the that, but the red wire (B+) just terminated at the rear fuse block (I have nothing connected to the rear fuse block at all) and the blue D+/61 wire went to the volt reg. So I can leave it that way.

Thanks for pointing me in the right direction.