could anybody tell me what the blue wire that comes off of the alternator. what do i need to do with it i'm putting a basic wiring system in my 944 and i need to know what to do with this wire. thanks for anyhelp

You should verify this but I'm pretty sure the blue wire is D+ as shown in this diagram. I drew this up for my own car but haven't done it yet. I don't have my wiring diagrams here to confirm the color of the wire.

The resistor is for excitation of the field. If you run without it, the alternator should excite at about 2K RPM. The car originally used the dash bulb to provide this resistance and an indication of the alternator not working if it didn't excite.

Hope that helps!

http://pages.prodigy.net/steruth/_uimages/wiringdiagram.jpg

Yep... it goes to the battery light in the gauge cluster. If it's not hooked up, the Alt won't output any voltage.

Actually the alternator will output voltage as it is self-exciting. You just have to rev it over about 2K RPM.

I know because my current gauges don't have a light but I do have a voltmeter. After I start it, I rev it up and the alt comes to life.

Good to know! Thanks! I only tested it while idle.

Sooo... if you rev it above 2k without the blue D+ wire connected and bring it back down to idle, will the alternator still output ~13.7 volts? Or does RPM have to remain above 2k for the alternator to 'self excite'?

Yes it will produce voltage at idle once it is excited.