Hi guys, just bought a 1996 A6 2.5tdi. She won't start on the key, but will work 100% on the bump start.

All of the lights on the dash come up fine when I turn the ignition on, but when I actually turn the key to start the engine, I just hear a faint click sound coming from the engine bay.

I've had the starter motor off and tested by an auto electrician, who says it's working fine.

So what else could be the problem here?

Is there a relay that might need replacing, or perhaps the ignition switch?

Thanks in advance 8)