With my aircon on full blast my ford ka constantly blows hot air through every vent. Even when the aircon and heater are off hot air is filtering through (more than normal from the engine). I have replaced the heater valve and problem still persists. I am at my witts end!
check heater control FLAPS are CLOSING when asked to do so, (watch the flap action open and close) the connection could have come loose in that the wire moves but not the flap.
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