B4 TDI, Alternator wiring

DubbedDiesel

Veteran Member
Joined
Oct 27, 2005
Location
Toronto, Ontario, Canada
TDI
1997 VW Passat TDI
Quick question guys. Is there a wire that runs from the alternator, to the ECU somewhere directly?? If there is, is it part of the main harness or is it independent?? Can't find anything except for the one that runs infront of the cylinder head.

If someone can tell me where all the wiring related to the alternator is, that would be great.

Thanks! Newbie stuff I know, but I'm trying to track down a gremlin or two....
 

Spulen81

Veteran Member
Joined
Mar 30, 2004
Location
Warners, NY
Yes there is, its called the DF terminal. It goes straight to the ecu. It plugs into the alternator with a 2 pin plug. The other pin is B+ which is basically for the alternator exciter trigger.. it is wired in with the warning lamp on the dash. It applies positive power to the alt. to tell it when to start charging. It will still charge without B+ but you have to rev it a bit for it to "kick" in.
 

DubbedDiesel

Veteran Member
Joined
Oct 27, 2005
Location
Toronto, Ontario, Canada
TDI
1997 VW Passat TDI
Hello Sir!! Thankyou for the reply.

Is this wire going to the ECU, a part of the main wiring harness or is it independent?? Where is it located / plug into on the alternator?? I'm actually looking for the DF load cable specifically. The only one I see is at the front of the alternator, facing the driver's side of the car. Is this it??

Please let me know. Thanks!!!
 

paramedick

TDIClub Enthusiast, Vendor
Joined
Jul 29, 2001
Location
Versailles, Kentucky
TDI
2015 Audi Q5 TDI
Two small wires, both black. Plugs in directly under where the positive cable bolts to the alternator. Comes out of the main alternator wiring harness area.

There is a second, larger, two wire plug with multi-colored wires.

I had a persistent code for the B+ trigger wire. It was cured with a recent voltage regulator replacement.
 

DubbedDiesel

Veteran Member
Joined
Oct 27, 2005
Location
Toronto, Ontario, Canada
TDI
1997 VW Passat TDI
Thanks Paramedick. I'm going to have to trace all these wires. I'm still getting a Code 01117 relating to a Generator DF signal fault. One of these damn things are causing some kind of short and the car keeps throwing a code. It has to be that 2 pin wire since it's directly sending a signal to the ECU. Is there a fuse or something on this wire? I've also got a really strange wiring short inside the car that I can't track down that I'm hoping is related to this. For some reason the car keeps thinking my key is in the ignition when it isn't....door chime sounds with door open, radio still plays. No battery drainage, just annoying door chime and lots of radio static. Ignition switch already replaced. Something went wrong somewhere... :(:confused:


 
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