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Hey, I have a E46 1999 323i sedan. I have no heat in the cabin and I cannot figure out why. The only time I get heat is when I unplug my heater control valve. BUT when the HCV is plugged in no coolant even makes it to the valve (both feed and return lines are cool. My temp guage performs as it should so my thermostat is working properly. So after testing my control valve I decided that it was an electrical problem (if I get full heat when the HCV is unplugged that must mean heater core is working and there are no clogs in the system. Its just controlling the heat that is my problem) So I purchased a new climate control dash unit. STILL NO HEAT. Seems like the problem is the heater control valve is always being powered therefore always closed. So what sends power to the HCV? its it the climate control module or something else? and yes, I have followed all the proper procedures in order to bleed the system, and have done it multiple times.

thanks in advance 😀😀
 

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The automatic climate control module (IHKA in BMWspeak) is connected to numerous sensors. These include the:
1. Outside ambient air temperature sensor located in the cavity between the left front wheel liner and the front bumper. This is critical for air conditioning but is used when using the heat. You can check the sensor’s operation using the button at the end of the turn signal stalk.
2. Interior air temperature sensor which is located in the IHKA. This isn’t your problem as you’ve swapped the IHKA.
3. Heater core temperature sensor which can shut off the heater control valve if it senses that the core is overheating.

I think the best thing is to have the IHKA scanned to see what item #3 is reading. But first check to see what the outside ambient air temperature sensor sez. If it sez the air temperature is ~122*F the sensor or it’s wires are shorted. Go to bimmerforums and search for threads using “INPA” in the search term and “Balidawg” is the poster’s name. Balidawg is the software expert.
 
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