[Rob. Smith]

I'm putting in an electronic thermostat for my radiator cooling fan. The old capilliary tube set-up was wired with the positive supply to the fan, switched by the relay. The positive supply was direct from the battery (fused of course) to the relay contacts. There is a lighter positive (switched) wire to drive the relay coil.
What I want to do now is use the switched supply to drive the electronics. No problem there and hook the larger unswitched positive supply directly to the fan and then switch the negative wire (earth) with the relay.
As all the other circuits are negative switched I can't see any reason why this one can't be done this way either.
Does anyone have a reason why I shouldn't do it this way.
The earths are very close and the power wire is fused before the fan.
Smithy.