Electrics mystery part 2!

[PhilS3c]

Finally getting the electrics sorted but I have one final connection that has me stumped. On the passenger side of the engine bay is a live brown wire (ignition on) as shown. No idea what this would be used for. Starter motors connected (to short to reach any way). Oil pressures connected, washer bottle connected. What else would need a live feed with a bolt on connection? Stumped again so any ideas please. Thanks Phil

[PhilS3c]

This picture shows the part of the loom the brown wire runs from. It appears to run down behind the washer bottle.

[SimonS1]

Looking at the wiring diagrams in Steve Heath's book, it appears that there are quite a few brown wires in the engine bay and most are the ground connections for various sensors e.g. air flow meters, engine and fuel temperatures. BUT the battery +ve is also brown so do not ground that!
Have you got a multimeter? If so you could check the resistance from the loose wire to battery +ve. If it's relatively high then you may be picking up the voltage through a sensor. That would fit with it being switched by the ignition too.

[PhilS3c]

Thanks Simon. I was working on the general principal that TVR used black earth wires. Must admit though based on the connector used and the positioning this wire certainly would make more sense as an earth wire as it is perfect distance to an earthing point already being used by the loom supplying power to the lights. So may just try earthing it and then see what happens !

[PhilS3c]

Hi Simon - connected the wire to the earth and turned on the ignition and the fuel pump tried to prime the system. So issue solved - thanks