Electric hob plate won't switch off

[mozziebait]

Hi,
The switch for one of the plates on my electric hob broke and now I can't switch it off unless the whole hob is off. It's on a high heat all the time so it's no good for cooking, but it's burning away while I use the other plates to cook.
I've opened the hob from underneath but don't know which wires to disconnect to stop it working. Can anybody help?