What Excites The Excitor Wire?

[Guest tomwp]

Hi,

 

I have a 1.9 GTI and have been having a few problems with the Alternator. The battery light has been coming on and it isn't charging. Having tested a few things I have found that the excitor wire (brown wire to alternator) doesn't have any voltage on it. I shorted it to the battery and the alternator started charging, the battery light also went out. So that eliminates a problem with the brown wire.

 

Where does the signal to the excitor originate from? On the schematic it just shows the instrument cluster.

 

Any help would be greatly appreciated.

 

Cheers,

 

Tom.

[Sandy 191]

It's basically a 12v feed (via a bulb and a diode to prevent back feed) from the ignition circuit, second click on the key switch.

[Guest tomwp]

So if I want to start trying to find out why there is no 12V signal should I start looking in the instrument cluster or on the steering column? Any pointers where to start? For the moment I am running a direct line from the battery and disconnecting it when I stop.

[Sandy 191]

I would look at all the connections in turn.

[Guest tomwp]

Just returning to this after being away for a few weeks.

 

I have removed the instrument cluster and checked the wire going to the alternator, the resistance is less than an ohm so I don't think it is that wiring. There doesn't look to be any burnt out component on the instrument cluster itself so that leads me to the wire coming from the ignition (position 2) to the instrument cluster. From the wiring diagrams I'm not sure which wire it is, any suggestions?

 

Thanks,

 

Tom.