Author Topic: VW Bosch Alternator Schematic? (Read 12215 times)

deepmud · « **on:** May 27, 2007, 02:45:55 pm »

In my "VW"

I have a 1997 110 TDI from CZ - it came with a Bosch 130 A alternator - I managed to keep the stock accessories with my Suzuki Conversion - I believe it's internally regulated. I can get the main power lug wired up easily - but control wiring plug was not sent with the alternator, I'll have to wire it myself.

Does anyone have a schematic for the wiring controlling the alternator? Like which would be 12v Key On, maybe one for the idiot light - and a constant B+ maybe?

somolovitch3 · « **Reply #1 on:** May 29, 2007, 04:51:03 am »

This the Alt with the Stud like posts on the back, yes?
Large post is 12 v from batt, little post is the "blue" wire from the ALT light that is fed when the key is on.
Rember to use 4 gauge (minimun) wire to ground alt to Batt Neg for best results.

deepmud · « **Reply #2 on:** June 12, 2007, 03:55:22 pm »

found a good pic finally - I know B+/12V is the big stud/nut combo - I'm not sure what the wires are in the connector behind it - I don't have that connector, looks like I'm going to have to tie in with something homebuilt to control the alternator. I think there are 3 pins inside that hole ( hard to see ) - which is Key On, which is the Battery Warning Light - and the third would be?

Vincent Waldon · « **Reply #3 on:** June 12, 2007, 05:36:52 pm »

There's likely no "key on"... alternators are on all the time.

Other than the big B+ stud that goes straight to the battery there are probably two other active connections.... one to the battery warning light that also provides the alternator with its initial excitation, and one to the tach (since it came from a diesel).

If there really is a third small terminal it might be for a noise suppression capacitor... pretty rare on diesel alternators for some reason.

Vince

Kudagra · « **Reply #4 on:** June 12, 2007, 06:45:52 pm »

Quote from: "Vincent Waldon"

If there really is a third small terminal it might be for a noise suppression capacitor... pretty rare on diesel alternators for some reason.

Vince

Lack of an electrical ignition system maybe?

Vincent Waldon · « **Reply #5 on:** June 12, 2007, 09:00:04 pm »

Maybe, although I think this particular noise suppressor is to suppress diode whine from the alternator... which is present in both systems of ignition. Perhaps it's to make life easier on the ECU of a conventional ignition car.

Part of the great unknown...

Vince

deepmud · « **Reply #6 on:** June 12, 2007, 10:48:39 pm »

I'll get a better look in there - see if there are three terminals - it will take a mirror now that it's in my rig. I'd like it to charge itself soon rather than just discharge the battery as I play around 4x4ing.
FWIW, this is a TDI-M, the alternator/engine was a 1997 Euro-TDI, from a Passat (SEAT actually). I don't know if the TDI would use the alternator, but I'd assume it takes tach signal from the ECM.

deepmud · « **Reply #7 on:** June 12, 2007, 11:42:34 pm »

this is helpful:
http://www.rangerovers.net/rrupgrades/electrical/boschalternator.html#wiring