Hi everyone,

I have a 2009 full-size RR Supercharged. The A/C and heat blow hot and cold just fine, but it's doing something very strange. For about 5 seconds after startup, all the vents work as usual, then I hear mechanical movement (like it would normally sound when turning off/on certain vents) and after that only the vents in the footwells and the rear seats work. This happens even if the dash settings are for specific vents and not 'auto'. I don't think it's the blend doors or motors themselves, since they each work at startup. It seems like there is a controller for the entire system that is getting confused. And again, blower and temp are working fine.

Any suggestions for diagnosis are much appreciated. Thanks!

David