Singlespeed fan
All the owner of this 2003 Ford Focus would tell us was that the heater wasn’t working. We attempted to pry more information from them before it arrived, without success. Once the car was in the workshop, it took only a short time to narrow the fault down: the heater was getting hot, but the blower would only operate if the fan was on full speed.
This is a common problem across a range of vehicles, usually due to the failure of the heater rheostat, also known as the resistor pack. On this Focus, the pack is fitted in the heater unit and accessed via the passenger footwell. Being bolted into position with just one screw, the replacement of the unit doesn’t take too long.
As soon as the new resistor pack was connected, we could confirm that the heater blower now operated at all speeds.