Hi yeah I hooked it up to my laptop running DIS (an older version of the BMW dealer diagnostic system) but there are no codes etc, and the temp readouts from the temp sensors are all normal (i.e. not reporting erroneously high temps).
When I change settings on the dashboard I can observe these changes reported in DIS (although I am sceptical whether that is just telling me that the IHKA recognises the request, and not that the flaps in the heater module are actually moving, although I can hear flap noises when I do this).
Thanks for the link - is there a way to test if my thermostat is working correctly? I always assumed it would have thrown a fault code that I would have picked up by now.
And also it is strange that the Heater Control Valve is mentioned in your link - I am so sure my car doesn't have this valve - I have had the bottom engine cover and top engine cover/micro-filter panel off & followed all the heater/coolant pipes in the engine and that part is not to be seen anywhere (and definitely isn't where it should be, which is in the engine bay, hooked into the passenger side front wheel arch, just where the heater/coolant lines run).
I'm gonna try to bleed the coolant tonight - I had a strange experience this weekend when I was changing brake wear sensors whilst waiting for the car to heat up to do some more DIS tests - had the passenger side of the car jacked up and the cabin heater was definitely working when I jumped in the car to reset the service indicators - as soon as I dropped the car back to the floor and went for a drive, it was cold again. WEIRD
Makes me think there might be air in the system and the car being on a tilt removed the airlock (but I didn't bleed the system at this point so the air may have gone back in)