I'm trying to install my Pioneer AVIC-Z3 into my 2006 RX400h to replace
the boring factory radio. After running wires for all the accessories for about 3 hours, when it was time to hookup the aftermarket system. I notice the HVAC is no longer working.

now I know once I plug the ugly factory radio back in, the HVAC system is back to normal, as far as I know it has to do with the plug on the factory radio, is this just data in, data out ? can it be reproduce to trick the system ? Does anyone have any idea how to work around it ? Many thanks in advance.

 

Installing a Alpine IVA-w505, I used a BeatSonic MVA-82 just for the 12 pin connector from the factory radio for the hvac and a Metra Tyto-01 for the 20 pin audio. This retained all the function except auto-mute during phone calls. I even keep the audio dim for navigation. The MVA-82 did not have to have power to work; so I am not sure if it was a simple wire bypass or if the unit processed any signal. I have so little time for this kind of stuff any more, it was easier to purchase something to solve the issue than track down the "cheap" solution and I did not have to destroy the Lex radio. I took the receiver out to get some factory work done but should get it back this week. My only issue was the face plate opening while in park.