Pump No Power: Golf III TD AAZ Valve Fix

Hello everyone,

I'm new here and have a pressing problem, and I'm hoping for your help.

'My Golf III TD (year 1992, engine AAZ) won't start. I've narrowed down the problem to the fact that no power is reaching the shut-off valve when I turn the ignition. I also tried applying 12V directly to the valve, and it 'clicked' as expected. My question is, what could be the reason for the lack of power? I suspect it might be a wiring problem, but I don't know where the wire (black/green at the valve connector) ends inside the vehicle (which terminal is it connected to?). Could it also be a faulty relay? If so, which one? The glow plug system is working correctly.'
Unfortunately, I'm not very knowledgeable about car electrical systems, so I would be grateful for any help.

Regards,
BanaSplit.

Hi! If the engine control unit isn't intentionally blocking the shut-off valve (e.g., due to a serious problem), you could temporarily run a 12V wire directly to the valve. This would allow you to keep the car running, and you could take your time troubleshooting the issue.

Regards,
Holger.

I might be wrong, but I have the feeling that 12V is being applied to the valve to keep it closed.

I might be wrong, but I have the feeling that 12V is being applied to the valve to stop it.

In my opinion, the motor will stop if the 12V power supply is lost.

I might be wrong, but I have the feeling that 12V is being applied to the valve to stop it.

It wouldn't really make much sense... eventually, I have to disconnect the 12V power, otherwise the battery will drain. Besides, the motor could just start up if you're only in park.

'On ships, shut-off valves are designed to remain closed even without power, ensuring continued operation in the event of a power failure.'


btw: the ignition switch is supposed to be a popular candidate...

CU Gremlin.

okok I believe you .

When I still had my AAZ, there was 12V when the ignition was switched on. I remember that once the connector came off during an overtaking maneuver on the highway. An embarrassing situation...
If I remember correctly, in my case it was a red-black wire that came more or less directly from ignition switch terminal 15. And I agree with Gremlin: the ignition switch could be the problem. I once had a similar issue with my 1Z. Terminal 15 was dead during the starting process. I'd check the ignition switch just for fun. If it's okay, then the wiring is probably broken. In that case, I'd just run a new wire.