Alternator wiring for a project with no loom!!

[dpetteng]

So, my rebuilt 1985 3.2 engine is going into my 1971 vw camper van. All the hard fab work is done.

I have to build a custom loom combining the ancillaries of a 1971 VW van and the electrics required for a 1985 911 flat 6 and gauges. The good news is it has been converted to carbs so no need for ECU etc.

In another thread I have been convinced to use a 1-2-3 distributor (because its mappable and doesn't need a CDI) so that's relatively easy.

The bit I am not clear of is where to wire the loom coming from the alternator to? from previous experience there should be a wire to the starter, one to the idiot light, and a few grounds and positives but I am not clear what colours or where they go.

Any advice on gauge wiring would be appreciated as well as I am using standard 1985 gauges. (Yes we built a 911 dash into a van)

Any help would be appreciated?

[timmy2]

For your van.
12 AWG yellow to starter solenoid.
16 AWG wires:
Green/Red to oil pressure gauge sender.
Green/Black to oil temperature.
Green/White to oil pressure idiot light.
Purple/black to Tach.
Blue to charge lamp from Alternator.
14 AWG Red from B+ Alt for constant power if needed.
8 or 6 AWG from B+ Alternator to starter.
Fat black from battery to starter.

Assuming you have other wiring for reverse and no blower motor.

[dpetteng]

That's awesome thanks so much. Just out of interest, why is there a wire from the alternator to the oil temp and pressure senders? Not something I have seen before?

[timmy2]

The alternator harness is normally part of the engine harness on the 3.2. All of those wires went to the original 14 pin connector (plus blower motor and it’s temp sensor wire)

That is a list of all the signal wires and their colors in a 3.2 engine harness that run to the gauges as well as the main alternator wires.
Which is what you mentioned as well. (Using the 3.2 gauges)

How you want to run them is up to you. Alternator has the fat red to starter, a smaller red for constant power to the fuse panel, a blue for the charge lamp at the gauge and a ground to the case.

[siverson]

This is good info, thanks!

I'm still trying to figure out where these wires should go on my 964 engine. All are exiting the fan shroud/alternator area.

Big red one - obviously +12V to the starter

2 smaller red - do I supply +12V to this or do they need +12V? I'm confused...

3 brown - all ground?

Blue - sounds like it's the alternator warning lamp.

Thanks for any tips!

-Steve

[siverson]

Photo of my problem...

[timmy2]

2 thinner reds are 12 vdc constant hot outputs.
Browns are grounds from alternator negative that likely used to connect to a device.

[siverson]

Thanks!

-Steve