My 03' Impala AC vents blows slightly warm on the driver side but blows cold on passenger side. This is the base impala 3400. The AC vents have dual controls.

I located the actuators for the right and left sides under the dash. When I move the temp lever I can see the actuator turn. Each side seems to be working. It's like the driver's side is not shutting off all the way. They are really hard to get to. Seems like the ashtray, climate controls and radio would need to be removed to get to the actuator.

Any suggestions?

Thanks John

 

We the A\C refridgerant gets low the drivers side starts to blow warm first while the lower side of the evaporator still get cold the air blow through it.
You need to top up\refill the A\C unit.