I can't tell if my dual zone A/C really works. If I set the driver's side to 80 for example and the passenger side to 65, I can't tell the difference. I was wondering if the air out the passenger side should be colder than the driver's side, but it feels the same.

 

You did not say what the outside temp was or how long you allowed the car to try and reach these settings. All this system can do to overcome the A/C effects is add heat to the side you want warmer, and that requires the engine to warm up enough to provide that heat.

You should notice the dual zone more when your car has warmed up and the temp outside is 30 degrees and you want 60 on one side and 80 on the other.

 

Operating Tips

When the engine coolant temperature and outside air temperature are low, the air flow from the foot outlets may not operate for a maximum of 150 seconds. However, this is not a malfunction. After the coolant temperature warms up, air flow from the foot outlets will operate normally.

The sunload sensor, located on the top passenger side of the instrument panel, helps the system maintain a constant temperature. Do not put anything on or around this sensor.

 

I'm talking about a fully warmed up engine. The temperatures have been summer temps. Just yesterday, the outside temp was 88. I had dual zone A/C in a 98 Chrysler mini-van and it worked so that is what I am judging this against. Maybe it works better when the outside temp is colder and the heater would be required.

 

Mine works fine in hot weather too. It isn't particularly useful for short trips if when the car has been baking in the sun. Get it on the road and after the cabin cools down it works as advertised.