Suit Most GQ Patrol Models
If your Heater fan will only work at One speed. 
There is a good chance that it is the Fan Resistor, mounted into the side of the Heater Box
And is Easily Accessible from Under the Glove Box.

As Air Con Was an aftermarket option there are some models that have a different resistor, 
so have a look behind your glove box before ordering and make sure it Looks the same