Heater Fan not working on speed 1, Speeds 2,3,4 ok

[lehapau]

Can anyone advise, heater fan not working on speed 1.
Speeds 2,3 & 4 work ok.

[rich r]

Most likely a burnt out resistor in the resistor pack.

The resistor pack serves to reduce the voltage going to the motor. It's got three resistors in it, of decreasing value. So in position 1, it dissipates quite a lot of voltage as heat. In position 2 it dissipates less, and less again in position 3. Position 4 supplies the full voltage to the fan.

There's also a thermal fuse on the resistor pack which is designed to cut all three resistors out if it gets too hot and so there's a risk of it melting the plastic duct that it sits in.

So if you've got position 4 only, it's probably the thermal fuse. If you lose just one position, but the other 3 work, then it's probably just one resistor in the pack.

The bad news is - you can't replace individual resistors, so will have to replace the whole resistor pack.

However - you might also want to check the heater relays are working too.