Heater issue on facelift Vectra Design CDTI

[G11DDS]

Hi

I have just brought a Vectra Design CDTI which has developed an issue with the heater. The heater is running on full blast all of the time and you can not switch it off, even if you stop and take the key out of the ignition it is still running.

Has anyone got any ideas on whats up with it as at the moment I have to take the fuse out for the interior module under the bonet to stop it draining my battery.

[MiniVauxhall]

Maybe the relay behind the glovebox have failed to contact all the time, not sure if this can happen tho.

[G11DDS]

It was really weird, I drove back from london and I stopped at a petrol station, it shut off fine then and then I drove a further 10 mins home and when I switched the engine off it was stuck on and I couldn't get it to turn off.