TD5 power query

[Fraz]

01 TD5 Defender 130

Is there a power wire somewhere that is only active when the engine is actually running?
I used the brown wire from the alternator, but there doesnt seem to be enough current to engage a solenoid. As soon as its connected, the battery light comes on too

I thought of using that wire to power a relay and then the solenoid, but its essentially the same as just a solenoid.

Cheers
Fraz

[Blknight.aus]

the oil pressure warning light.

its on when the engine stops but its easy enough to wire up a relay to that and the ignition relay so that when the engine oil pressure light goes out the relay contacts change over.