Blower fan not working...

[Umai Naa!!]

I'd say it's the fan speed switch.

It has copper contact strips behind the control knob, that over time, build up corrosion, or are simply not making contact.

The ticking noise was probably foliage (leaves, etc), falling into the fan from the ducting under the pollen filter.

[Flat-Mango]

Lucky i've got a spare around, I'll give it a swap and check.

More info: I remember it not working sometimes, but when i gave it a rev, it would kick back in.
Also 4's force would flucturate and was slowly becoming weaker day by day. Now it's same speed all round.