The alternator on my 1975 1.8 has one thick red wire in a brown sheath going to the large terminal on the starter. The alternator on my 1973 2.0 liter has three wires in the brown sheath, two thick wires one red/white and one red/black, and one thinner wire that looks like it might be gray. Which wire(s) should I hook up to the starter from this brown sheath? Pictures below.
Wire from alternator on the 1.8
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Wire from alternator on the 2.0.
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The alternator on my 1975 1.8 has one thick red wire in a brown sheath going to the large terminal on the starter. The alternator on my 1973 2.0 liter has three wires in the brown sheath, two thick wires one red/white and one red/black, and one thinner wire that looks like it might be gray. Which wire(s) should I hook up to the starter from this brown sheath? Pictures below.
Wire from alternator on the 1.8
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Wire from alternator on the 2.0.
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I don't know but I suspect it has to do with the rear window defogger. I have been making new harnesses and was looking at t examples of the alternator harness. One was not as shown but the wires were different at the repay board end. i would look there next

Ok, here's a picture of the relay board end of the alternator wiring brown sheath. There is one large red/white wire with a female spade connector on it and it is continuous with the red/white wire on the stater end sheath. So it looks like the red/white wire may feed current back from the starter connection to the relay board (I don't have a relay board, so It looks like I might not need this wire), and the red/black wire at the starter may be providing the alternator output current.
Other wires on the relay board end of the sheath are two connectors. One connector plugs into the voltage regulator slot on the relay board or directly into the voltage regulator in my case. The other connector on the relay board side of the sheath is a three wire plastic connector that has blue, black, and gray wires going into it, gray and black wires come out of the sheath and the blue wire comes out of the voltage regulator connector. I think I do not need the three wire connector either, but I will need to splice a switched hot wire with alternator light into the red wire on the voltage regulator connector to provide current to bootstrap the alternator on startup.

So basically I think I can connect the large red/black wire at the starter and the voltage regulator connector at the regulator and plug in my alternator light wire and everything should work, hopefully. I would not be using the large red/white wire or the plastic three wire connector. Any thoughts on this?


Picture of relay end of alternator wiring sheath.Click to view attachment

You forgot the pics?

That last photo appears to be of a VW T4 alternator harness, not 914. Get the correct harness for your 914.

This is what the alternator harness looks like. It does not attach to the starter.
Pay particular attention to the rubber "cap" on the side that goes under the ventilation cover for the alternator. If the positive touches the metal bad things happen.
Also check for brown (burnt) discoloration on the outside jacket.

I have never found a rebuilt 914 alternator that would work with the cover out of the box. The stud for the positive connection has always been replaced with one that is too long. Get a thin 8x1.25 nut and bolt the wiring harness to the alternator. Then take a dremel with a cutoff wheel and cut the stud off flush with the top of the nut. Put on the rubber boot, then the metal cover. Once that is on, use a DVOM and check continuity between the positive wire and ground. Most meters have this as a setting where the meter will beep if there is a circuit. If it beeps, pull everything back apart and go back over everything. If you don't have the beep function on your DVOM, look for 0 Ohms resistance. You will always see some resistance in an alternator, but 0 Ohms is a dead short.

A short here will let the magic smoke out of the alternator harness.... very rapidly and spectacularly.

@motorvated

Do the two alternators look the same? Mmn maybe you have a VW alternator. All 914 alternators have the three pole connector with spade terminals. I dont know how you would connect ring terminals on your harness to spade connectors on the alternator

I believe the two alternators look the same, but it's hard to say for sure since both are installed on engines at the moment. The harnesses are clearly a little different, so one might be a VW alternator. Since it is such a pain to remove the alternator with the engine in the car, I was hoping to figure out how the odd harness can be hooked up. Since the "relay board" side of the harness has the three prong connector that mates up with the voltage regulator, that seems the same as my old harness and I can plug that in. On the "starter" end of the harness, I think the large red/black wire should get hooked up there, as I think it originates at the B+ terminal inside the alternator, but with the alternator in the car I can't remove the rear plate on it to confirm. The large red/white wire seems to just be a continuous wire within the harness that goes from the starter end to the relay board end would not be used in a 914 application.

So does anyone know if the large red/black wire at the starter end of this harness originates from the B+ terminal inside the alternator, and can anyone confirm that the large red/white wire does not originate from within the alternator and is just a runner wire within the harness itself. There is no continuity between the large red/black and large red/white wires of the harness.

The schematic is posted above, use your ohm meter to confirm the circuits.

The starter is part of the ignition harness that plugs into the relay board with the male plugs.
I'll post up a pic as soon as I'm in the shop.

My harness tests out consistent with the schematic provided above, so I think I'm good to go with it. Thanks everyone for your help.

My harness look like that one. Does the gray wife also attach to the starter.Click to view attachment Click to view attachment