Heater/air con fan speeds

Isn't your heater supposed to blow hot air?

When you select A/C or Heater, there is a door (vent air flow change) that open and close when making these selections.

I would first check the fuses and relays in the fuse/relay box in the engine compartment on the drivers side behind the battery along the fender edge. You can use other relays that are already in there by swapping the A/C fan relay with the wind shield wiper relay. You can either use the labels on and in the cover for the fuse/relay box or from in the owners manual if you have one. That's where I would start, I hope this info helps.

What type radiator fan do you have? Fixed cconstant , viscous variable speed or electric?
Does it run cooler at highway speeds above 35 mph?
What is the pressure range on the radiator cap?
Is the coolant mixed at approx. 60/40?
Is the condensor and radiator clean and able to pass enough air?
Is the fan shroud on?
Genuine concerns, let me know, good luck

the blower motor has no affect on the AC system,
start the engine and turn on AC and watch the AC compressor to see if clutch engages,if it doesn't the system isn't full,if you are correct the clutch should be engaged and should quit when you change heater speeds,

you have a bad blowermotor resistor.change it and problem is gone, good luck.

Find Someone else,
Have Them Replace The Fan Selector Switch,
There Is Only 1 Fan In The System, Since You Can Select Between Defrost, Dash, Floor,
But Cannot Control Fan Speed/Shut-Off Fan.
I Would Replace The " Fan Selector Switch" Installed In Your Heater-A/C Controller Unit
Mounted In Your Dash.
Take Care God Bless

you need a resister found under your air duct by the passenger floor under dash board auto zone sells these for about 25.00 you may as well buy cabin air filters while your at it . 1 of the screws will be a pain to install back into the duct work I left mine out didn,t make a difference . you might have to order it as they are a comman item oh you will need a vacuum to clean up mess from cabin air filters .this is not a hard job .

When you find the fuse if it has blown also check the resistor to control the fan speed. I cant remember if the 1 series has a load resistor multi tap but it may have failed if you use 1 or 2 speed on the fan a lot, max will bypass the load resistor where as 1 will use maximum load and the thermal fuse might have blown. But replace it as caution. In the earlier models it had a block which was nicknamed the hedgehog, a load resistor buried under passenger foot-well up toward the centre, loads of spiky aluminum pegs which cold air blew over to cool it, always packing up in the earlier models £25 from scrap dealer cheap fix compared to the £££££££ BMW dealers rip off. Heater or air con would either not work or blow erratically. Hope this helps

The heater resister switch has gone. You need to strip out the box and put a new switch in which costs around £20