Originally Posted by Johnno
Can anyone suggest the next move? The heater fan isn't working on any position. I've checked the resistor pack any it appears to be in good condition. There is power both sides of the fuse. There isn't any power reaching the switch. I was going to start tracing the wires but without a wiring diagram this is not easy. Haynes apparently don't do a manual so getting hold of the wiring diagram means paying bug bucks to Rover. Any help would be appreciated.
Basically the resistor pack, and the blower rotary switch, are both in the 'earth' side of the blower motor.
That's why you had power both sides of the fuse, but not at the switch.
In the resistor pack ,there are three resistors wired in series.
Position1, switches all THREE resistors in series with the motor to give the slowest speed .
Position 2 switches TWO resistors in series with the motor to give a slightly higher speed.
Position 3 switches ONE resistor in series with the motor to give a slightly higher speed again.
Position 4 bypasses the resistor pack completely, to take the -ve side of the motor to earth to give the highest speed.
If you've checked the three resistors in the pack and none are open circuit,
and the blower wont work in ANY position. Then it points to either a faulty rotary switch, or a faulty blower motor.
The blower motor can be checked by tying the -ve side to earth then switching on the ignition.
HTH ( even If a little long winded!!).