Can someone tell me the voltage this is at? I'm guessing it only needs to send a signal to say whether the handbrake is on or not, so it cant be much...

I'm guessing 12V?

Could be just a switched earth, can't remember off hand. Need to have a look at the cfd to confirm.

One side of the warning light is supplied with 12V and the h/b switch earths the other side of the light when the handbrake is engaged.

cool thanks guys