Air Conditioning Control Panel does not Operate: Description
WARNING: This page is about a different car, the 2008 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.
This circuit consists of the air conditioning control and the air conditioning amplifier. When the air conditioning control is operated, signals are transmitted to the air conditioning amplifier through the LIN communication system.
If the LIN communication system malfunctions, the air conditioning amplifier does not operate even if the air conditioning control is operated.