Only hot air - Not Final Stage or Heater Control Valve

So I have a 330ci with A/C and ever since I have owned it only hot air comes out regardless of the temp setting.

Having had a leak in the expansion tank I decided now was the time to get the heater control valve changed as most posts I find route this as the cause of the problem.

Changing the heater control valve had no effect so we fitted a new final stage resistor at the same time... still no luck. The computer still pointed to the heater control valve as being faulty so another part was obtained from BMW and fitted.

Still only blowing hot.

The system was properly bled by the mechanic and they just can't work out why with all the parts changed it's still blowing hot only.

So after a big bill I need to find a solution to this problem.

Have a look at the little fan in the back of the control unit. Pull the stereo out, then pull out the climate control panel. Look at the back and see if the little fan is spinning....Mine wasnt and it was doing all sorts of odd things...(managed to jam it with my ipod connector)

um...if you are only blowing hot, maybe you are out of freon? it may be a problem with your a/c system, not your heater

With or without aircon on its hotter than the surface of the sun.

lol I wish I had your problem! I can't get any heat!

I'll swap with you!

Bad temperature sensor somewhere? There's one integrated with the climate control head unit, no?

The left grill on the control unit has a sensor behind it but this is only used for 'Auto' ambient temp control... shouldn't interfere with the 16 - 32 setting so long as auto is not selected.... unless im wrong about that

Originally Posted by Trackitdown

The left grill on the control unit has a sensor behind it but this is only used for 'Auto' ambient temp control... shouldn't interfere with the 16 - 32 setting so long as auto is not selected.... unless im wrong about that

My understanding of how the climate control works is as follows: you select a target temperature and the climate control computer compares the ambient temperature to the desired temperature and adjusts the heat/cool blend appropriately. A bad temperature sensor would throw that all out of whack, no?

sounds liek the blend air (hot/cold) flap motor is out. Usually when the temp is close to ambient temp is a a/c problem. But if its way hotter than ambient air the blend air door is stuck at hot. hot vent temps and hot engine temp is obstruction to air flow. and yes if the outside temp sensor has been torn off the car (located bottom of vehicle attached to bottom right splashgard or left... i forgot) it can throw off the temp out put i havnet seen abnormaly high temps only warm temps.

Originally Posted by imlostathome

sounds liek the blend air (hot/cold) flap motor is out. Usually when the temp is close to ambient temp is a a/c problem. But if its way hotter than ambient air the blend air door is stuck at hot. hot vent temps and hot engine temp is obstruction to air flow. and yes if the outside temp sensor has been torn off the car (located bottom of vehicle attached to bottom right splashgard or left... i forgot) it can throw off the temp out put i havnet seen abnormaly high temps only warm temps.

Ya, but what about an interior temp sensor failure?

Originally Posted by blarf

Ya, but what about an interior temp sensor failure?

The internal temp only matters when the system is in auto mode. His system blows hot air all the time... just like mine unfortunately...