Hello - 2012 Suburban LT (Z71) and trying to find a way to be able to block fresh air intake without the AC running.

Currently, if the HVAC is not running cannot activate the recirculate button. If the heat is running cannot activate the recirculate button. My understanding is this is to reduce moisture buildup up and help with O2 levels in the cabin.

However, there are times I want to keep outside air from coming in, for example, if driving by a cattle ranch, or there is an old non-maintained diesel truck in front of me.

Can the actuator be reprogramed or replaced with an aftermarket kit so it can work just like the newer model vehicles do?

 

Recirc only works with system on. It's designed that way so fresh air goes into the inside when ever possible to prevent any possible exhaust or carbon monoxide from getting inside if system is off or on .
There is no factory or aftermarket to reprogram the recirc.. Putting in a air filter kit with a carbon filter is the only thing and that will not eliminate strong odors.

 

Nifty trick learned yesterday to share with forum:

If you set the fan to blow in both top and bottom vents, then you can activate the recirculate mode with the hvac off!