2008 Acura TL has a "dual" switch so passenger can set their own temp, right? So, dual switch is off, set to blow on "Lo" both sides yet warmer air on passenger side vs cold air on driver side.
I've switched the temp up to "hi" and or like 80 degrees, then back down to lo and still blowing warmer on passenger side as if the opening/closing of internal vent is not closing all the way OR the control module itself is bad OR I don't know.
Please help!

 

Welcome to the forums.

This thread has been moved from the First Generation RDX (2007-2012) > 1G RDX DIY & FAQForum to the car specific forum applicable to your vehicle.

 

Generally one of two things..

1.) Low on freon charge
- this is what the dealer always "claims" is wrong with mine

2.) The blend/mix door is sticking

I have similar issues as you, just opposite sides. My '05 has been like this for I think 7 years now? As long as I don't touch the Dual option, it is mostly ok. You flip to Dual, and the Driver's side stays quite a bit warmer than the passenger side. There is a diagnostic you can run on the system which will report back if it can identify a failure...."if" is the key word there.