Extra lead on positive battery cable

[daveyboy1967]

Hi all, looking for a little help as this has me stumped. I've just changed the battery on my '03 A6 1.9TDI and there's an extra lead spurred off from the positive battery cable about 6 inches back from the terminal clamp. It looks like it's OE rather than a DIY botch job for an extra power lead and it's about 12 inches long with what appears to be a sensor on the end (could be a terminal/connector of some sort but I've never seen one like it). I don't think it was connected to anything before I got started on the battery swap but it could be that I inadvertently pulled it loose when I removed the old battery. I can't find anything for it to connect to within reach of the cable so I replaced the battery and left it loose. Everything is working fine as it did before but it must be there for a reason. Does anyone have any ideas?

Thanks in advance,

Dave

Edited Saturday at 04:07 PM by daveyboy1967

[cliffcoggin]

A decent photo might help in identification.

[daveyboy1967]

Yeah, I realised this after I finished. I was hoping someone might know before I pull the scuttle etc off again. Kicked myself after mate.

[Steve Q]

I can't say my A6 has this (2.5tdi). Are you sure there's no additional electrical equipment fitted? Or previously fitted? 

Do you know the cars history? It must have had additional bits added if it was a working vehicle. 

Signs of this would be holes drilled into bodywork or interior. Or unusual blanking covers that look out of place. 

Alternatively follow the wire to see where it goes. If it goes towards the engine bay could it be for electric fan?