I have a Mk 3 Mondeo on an 03 plate. I noticed recently that the heater was constantly blowing cold air and am about to replace the thermostat as a matter of course. I found out last night though that the a/c compressor is running when the engine is on despite the a/c button being switched off. I removed the fuse in the battery fuse box and the compressor turned off, i swapped the relay with the horn one as they are the same to see if relay was at fault but it wasn't. Can any one help?