Live Wire

Hi all
Can anybody help me out. I have a 2004 Td5 and I need to find a live wire that only becomes live when the engine is running preferably under the bonnet I have been out with a test light for 3 hours and i found every thing but. ......Many Thanks...Tony

when engine is running or when ignition is on?

if engine is running, then surely the back of the alternator would be a good place to start?
I take a feed from there for my split charge relay.

Hi its needed when engin is running i did consider the altinator but i was'nt sure if it would effect any thing else...Tony

there should be a little wire to the back of the alternator, dont use the fat one that goes to the battery as this wont work.

Use your light to check it's giving you a reading when your engine is on.

Thanks for that have just been looking at the alternator found the fat one constant live and i can see 2 small ones 1 white and 1 brown i presume it will be the brown one i want but the problem i have now is getting to it there is loads of things in the way. Could you confirm if it is the brown or should i try them both. From what i can see they are both on a plug at the back but i can't seem to free it....Thanks again...Tony

Look for the terminal marked "m" on the back of the alternator that one is only live with the engine runing As yours is a diesel it runs the rev counter as well.

Thanks for all your help i managed to do it, it was the brown one. 4 scaby knuckles and apulled shoulder but HAPPY...THANKS

Found one in the fuse panel(dash mounted) which have nothing connected and a S13 mark.Anybody know what is this linked to, as I want to connect my Kenlowe fan on it?
My car is a '99 td5 LHD.