I installed a Car play system where my radio was in my 2009 Pruis and after the install the upper screen has a "Check connection to Air conditioning" message and there is nothing on the battery display it is just empty and blank. I can still drive the car and control the AC through the steering wheel how every can not see any AC controls on upper screen how can I fix that?
Your post is the only one found by Google containing "Check connection to Air conditioning". That is very odd. Is that the exact message? Pretty sure the radio had no direct electrical connection to any part of the HVAC. So the way you fix it is to figure out which wires were improperly routed or damaged when the car play system was installed. As a first step I would try unplugging all the connectors to the new device, and any adapter cables it used, to see if the message on the MFD goes away.
The radio does not, but the MFD does allow control of HVAC and the radio. Some socket/cables are likely not connected if this issue arise.
