Check wiring to heater valves.
Got my car looked at yesterday, and thought I would post the results in case anyone else gets a similar problem. Problem
Always hot air out of screen and feet vents when opened. This was whatever the temperature setting and whether the aircon was switched on or off.
The aircon did work out of the face vents and was controllable via the dial between the centre vents.
When the car was rigged up to the diagnostic computer there was no communication between the computer and the climate control unit. The mechanic deduced that because of this and the fact that when the climate control unit fails it will always fail to hot air (BMW feel this is safer than cold, especially in winter)! that the climate control panel was defective.
The choices were, recon. panel from BMW £207
, or from a breakers £99.
The breaker asked what the fault was before finalising the sale and told me to check the heater valves (£30 its getting cheaper) before replacing the panel. These are situated (RHD) against the passenger side bulkhead and are two small aluminium cylinders with about three heating pipes and one connector attached to them. Sure enough, two of the three wires to the valves were melted and severed by the heat from the valve body.
10 minutes later, after putting some new connections on and extra insulation tape I had aircon that worked.
Just thought this may help somebody, it might be worth checking the wiring even if you don't have a problem, yet!!!
Thanks for your suggestions