Quick question, I know all you knowledgeable 914'ers must be burnt out on electrical questions, so I'll keep it breif--for now . My 74 1.8 isn't charging but the light will go off on the dash and when the alternator is unplugged and re-plugged into the main harness you can notice a parasitical loss...but it doesn't read that it is charging when tested on the battery. There is a red w/ white stripe wire (seems to be a live wire) that has been snipped off the alternators harness...what is this for? where does it go? could it be the problem? Any ideas would be a lot of help. Thanks.

I am a newbie to the 914 land, obviously.

Well by you seeing the light on the dash go off tells us part of the wiring is intact and working as designed. I have a V8 and a GM guy but many charging systems, older units use three wires as its core circuits. One as you have seen above working and the another would supply battery voltage (12 V). I don't know how the 914 delivers the voltage but surely it needs to be there when the engine is running, may be there with the ignition on. The third is also battery voltage normally hot all the time with the key on or off. The first wire normally is the smallest in size, the second is next and the third is the largest gage. I would make sure you have voltage at the second and third wires. Thats a simple way to check the harness in many older systems. I really don't know how the 914 is configured so hopefully once someone reads this they will chip in with Porsche comments.

The alternator harness has four wires. Three are small diameter wires that terminate at the plug on the relay board and then connect inside the board to the voltage regulator. The other wire is a heavy wire from the alternators D+ terminal that goes to the post on the starter that the battery cable is connected to. Check this wire first, it is sometimes left off when the starter has been removed.

It is the heavy red/white wire that is cut, not the lighter gauge wires. The heave guage is supposed to go to the starter? It comes out at the same location that the light gauge wires do--right at the relay. And it is live. If it is supposed to go from the alternator to the starter why does it come out at the relay? Am i supposed to take the wire all the way back through the engine compartment to the starter? It doesn't seem like this is the way the harness is set up. Would this wire disconnected cause the car not to hold a charge? So many questions....

thanks again.

Barretta,
The book I have has three wires from the relay plate to the alternator. Followed this book ( HAYNES manual) and just got mine running yesterday.At the alternator you should have four wires , the three from the relay plate ( D- , D+ , anf DF ) and one really large one from the terminal on the back of the alternator to the starter. This large wire ( 6 or 8 ga.) is the wire that carries the charging current form the alternator to the battery. It goes on the same post of the starter that has the positive battery cable on it.
Hope this helps.
Tom

Alright, thanks for all the help, and quick. But I still don't understand why the heavy gauge red.white wire comes out at the end of the harness--where the three small wires go to the relay. It's definitly a live wire, but where is it supposed to be hooked back up to? Run it back to the starter? Battery post? I am confused.

The reason you would run it to the starter is because the starter has a post on it that goes directly to B+. Thus, you would be connecting directly to the battery. If this wire is not hooked up you will not charge your battery as this IS the output to your battery for charging (Vin).

I follow what everyone is saying...and the help is greatly appreciated. But I still do not understand why the live wire is coming out of the same harness that the red/white wire is. Does it hook somewhere on the voltage regulator? or relay? It wouldn't make any sense to run it all the way back to the starter...would it?

i think it's time for some pictures ... show us what you got!

Here is the picture... hopefully someone can tell me whats up. Notice the 10 and a half million wires (slight observation) that come off this harness...when there is supposed to be 4? And the red/white wire is clipped. Thanks guys

Well your pic will help you better understand what we were trying to say. The tree wires on the plug are obviously the wires for DF, D+, D- for the alt. The other two going to the rectangular plug look like the blower fan power wires and are of no consequence. The Red on as stated goes to the B+ on your battery. If I am thinking correctly (not always right of course) then running your car with that red/wht wire detached is like having your battery disconnected while the car is running which = dead diodes in your alt = new alt. So dont do it! If your alt is already dead the PO may have cut the wire because it was causing a fault in the circuit. Not correct.

So, if the red/wht wire is hot when alt is turning = out put to B+ if it is directly connected to B+ already (cheack with meter) then it is to have had a terminal lug on it that went to the alt.

Clear as mud?

The red.white wire is hot all of the time. So that means it is from the battery, correct? I ran the car like this for hundreds of miles, but it obviously didn't charge. So, I will try not to be completely thick headed...but in simple terms. where does this gosh-darned wire need to go to? I need to buy a new alternator/VR, I'd like to know what to do with this wire if it is killing my alt. It doesn't make sense to me to run this wire back to the alternator from its current location, but thats what needs to be done?

Ok, it is hot all the time so it is the volts into the battery from the alt via the starter where it interconnects.

I do not have my Haynes manual in front of me right now and I can nopt remember what the back of a /4 alt looks like, but you should have a terminal on teh back of the alt that looks to be isloated from the surrounding metal. This is the V out. You will need to elongate the wire and put a ring terminal connector on it to mount it on this terminal. That is it. If you look at teh back of your alt it should all become painfully clear. I would test the alt you have first to see if it is bad or not. You can take it to most FLAPS and have it tested. I am not sure if the VR gets fried in the equation. One step at a time.

1) attach wire to alt in right spot. 2) test alt either in car or on bench. 3) if alt good put in car and see if it charges. 3b) if it charges put a load on teh battery (lights, radio, etc) and see if the volts eitehr go up a little of at least stay the same at about 13v. If this happens your VR is good. If not get a new one.

Hey again. Here is the deal... there is no way that the red/white wire is supposed to be ran from the engine bay by the relay board back down to the alternator. Besides there is already another red/black wire that runs from the starter to the alternator..i imagine this is what you were suggesting i do with the red/white wire. However, the red/white wire is connected to the same terminal on the starter, so i am guessing that is why it is hot all of the time. So, how many wires should be going from the alternator? I have 5: the red/black, which goes from the starter to the alternator; a yellow, which goes to the relay board; a thick brown, which goes to the ignition (i'm guessing); the black to the batter; and finally the red white which is clipped. Why is it there, what to do with it?

Your picture doesn't look like the alternator harness of my 74 2.0, nor does it look like I remember my old 1.8 looking. Perhaps you have the wiring from some other car in there? (Don't laugh; it wouldn't be the first time Bus or Bug parts got used.)

The fan wires in the 74s were in a different wiring harness, not the alternator harness. On my car, they're in the one that lays along the top of the diagonal "frame member" going up along the side of the engine bay, under the relay board. There is a sub-harness that splits off containing the two fan wires.

The alternator wiring harness on my car has two branches--there is only one where it leaves the alt, but it splits partway back. One branch goes up to the relay board and contains only the three alternator control wires (brown, red, green). The other one goes back through the vertical engine tin, and has the thick red (no stripe on mine!) wire with the ring terminal on the end that carries the charging voltage to the starter.

Your wiring is obviously different; I believe it to be non-stock. Which is why everyone seems to be unable to quite understand each other.

--DD

Maybe this will help..... I simplified the wiring diagram to show just the charging circuit stuff....

Click to view attachment

Thanks for the simplified drawing. After staring at the Haynes manual for one hundred hours, I have most of that figured out...what it is 'supposed' to look like. Would the harness be out of an older 2.o car perhaps? The five wires off the starter still get me... but it starts and runs fine, just doesn't charge. I'm putting in a new alternator and v. regulator...we'll see what happens. How do you i.d. the engine? Is it as easy as good 'ol US cars?

So, does anyone think this could be the wire harness off of the earlier 2.o's?

Nope. The 2.0 alternator harness is as I described--just the wires for the VR, plus the fat charging wire.

Drop Jeff Bowlsby a note ("bowlsby" here on the BBS) about the harness. He's messed with quite a few, and he might have some notion of what this harness is from. I think he can also set you up with a new/reman harness. http://members.rennlist.com/914_wiring_harnesses

--DD

Put a new alternator in and VR and some new wiring here and there...and it seems to work (knock on wood and all that). Feels good to drive it again. Thanks for all the info. A real tried-and-true American-built Dodge kid like me has falling in love with a Deutcheland gem.