A/C blowing half cold and half hot

Welcome to 2CarPros.

The expansion valve has nothing to do with this type of problem, so I question why they suggested it. Since the AC is cold on the one side but not the other, the AC system is working. However, it sounds like what is called a blend air door actuator has failed. This actuator is what is responsible for determining the temperature of air entering the vehicle.

I attached a picture of the actuator for you to see. Most vehicles refer to it as a blend air door actuator, but on this vehicle it is referred to as an air mix actuator. See the attached picture.

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What I would suggest is to remove it and check it for operation. If it fails, here are the directions for replacing it. The remaining pictures correlate with the directions.

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2010 Mazda 3 L4-2.5L
Air Mix Actuator Removal/Installation
AIR MIX ACTUATOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER]

Driver Side

1. Disconnect the negative battery cable.

2. Disconnect the connector.

3. Remove the hook (1), remove the rod (2) from the air mix actuator link.


pic 2



4. Remove the screw.


pic 3



5. Remove the driver side air mix actuator.

6. Install in the reverse order of removal.

Let me know if this helps or if you have other questions.

Take care,
Joe

Forgot to mention dealer did say I have really high, high pressure. But can actuator cause that? Since the actuator cause the door to let in hot air now the car is trying extra hard to cool but doing complete opposite, hence the high pressure?

Welcome back:

No, the actuator wouldn't cause that to happen. It sounds like you have two different issues. Something in the AC system may be plugging. Do you remember what both the high and low side pressers were? Also, approximately what the temperature outside was when it was checked?

Joe

low was 10 psi and high was 300 psi, temperature is around 95-100 here but it was inside the dealers garage so it might be a bit cooler. ac expansion was replace first, but that didn't solved the issue and then condenser was replace as well and for a moment for two days everything seems fix then all of sudden it's back to square one. feel like something is restricting on the high side but compressor is in good condition.

Welcome back:

If the expansion valve was replace (that would have been my first suspect), then you need to flush the system. I agree with you. Something is causing a blockage.

Let me know if that takes care of it.