The brake lights are on on my daughters beetle, they won't go off. Just pulled the wires off the master cylinder and they still stay on. Any idea where I should start looking?

I think it works the other way?

Short the wires you pulled off together and the light should go out

No it doesn't.

Are they only on when the ignition is on?

They should only come on with the ignition on and if you touch the 2 wires together.

If they are staying on without the wires touching or connected then its probably a bad ground causing feedback or the 2 brake light wires down to the master cylinder switch are worn through and touching each other in the loom somewhere.

Thanks, looks like I best look at the earths. Yes they only work with the ignition on, and when I connect them at the master cylinder they stay on still, only one wire is live here thou.

Ok all fixed, turned out to be the front plug on the master cylinder that's not hooked up, not sure how I only had power to one wire when I checked, must have been a dodgy earth on the test light.