PenR

Hi all - I am at my wits end and also the limits of my auto electrical talent because all of a sudden the heater blower would not turn off even with the ignition off and key removed. This flattened the battery so I pulled the 30amp fuse and recharged the battery and set about fault finding. I figured it had to be the resistor/rheostat so got that out and bought a new one but got the same result. Ok so maybe its a failing relay (could not find it!) eventually figured it must be behind the heater control knobs so removed the unit - got hold of a secondhand (guaranteed) unit and fitted that. Same bloody result!! The switch was sending the correct incremental voltages so what the hell is it? I have fitted an interruptor switch to the RED cable from the resistor to the blower motor so I can use the car but I need to sort this properly - so, any help or advice would really help please!!!!
Thanks in advance
PenR