Next problem - heater noise/aircon

[Technoholic]

Next issue on my list is a problem with the heater and air con.

Air con doesn't do anything, doesn't get cold at all.
Heater temperature selection doesn't do anything, temperature stays the same throughout the range.
When blower is on low, everything seems normal, but turn it to anyway from about 25% power upwards, I get a knocking/rattling noise around the passenger dash side of the car. I can only describe it as a metal ball trapped inside the metal air vent that's being blown and banged around, although I'm sure it's not as simple as that.

Any pointers on how to diagnose these issues?

Thanks

[dvs_dave]

Sounds like the blend door has become detached from the stepper motor, or the stepper motor has failed. Take off the heater airbox and have look, see if it’s working or not.