Problems with climate control on 2000 BMW

[Hilton]

I have a 2000 BMW. I replaced the battery on it about 4 months ago. After doing this the air conditioner will blow hot air for no reason. The air conditioner can be off and the hot air still comes out. The truck has dual climate control where the driver and passenger can be at different temps. What's more, if I turn the truck off and back on the problem corrects itself. Does anyone have any suggestions and what problem could be? If I DIY, do I need the autocom cdp diagnostic tool for it???

[JCL]

If the heater/AC fan blows unexpectedly (not when it is supposed to, and sometimes when it isn't supposed to) it is often the Final Stage Resistor (FSR). It is essentially a part of the fan control circuit, but it is electronic, not just a resistor. It is fairly easily replaced. It is mounted under the dash. No coding is required. Do a search for a DIY article.

[Hilton]

But there have somobody told me that the temp mode door actuator is bad. Do you agree with it???

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Allobd2

[rogerkiu]

Most likely the controller is bad, you may have to replace the controller.

[ake53]

having the same issue. tried recharging it with r134a. the proffesional way, gauges and stuff...

still have the proble of the middle right vent, the rear vents, and passenger feet area blowing hot while drivers blowing ice cold. the knob is on the three blue.