Turns over slowly but won't start

[bestseany]

Hi guys,

My 2002 1.9 TDI passat was working fine 2 days ago when I last used it. However, when I've tried to start it today it turns over 2 or 3 times really slowly and then stops until I try the key again. It won't actually start at all.

When I'm trying to turn it over, all the lights on the dash go really dim, and the clock and climate control have reset as if the battery has been disconnected. I thought the battery was knackered, but it's showing 12v on the multimeter. When I jumped it from a Nissan Micra, it did exactly the same thing so I don't think the battery is at fault.

The problem feels like it might be a dodgy earth, but I've had a look and can't see anything that looks suspicious. Is there any problematic earth cables that I can check? Where is the engine earth strap? I haven't been able to find it.

I''ve done a fault code check and nothing is showing. Does anyone else have any suggestions? This is quite urgent, I need it for work!