Hi bro. My nissan sylphy (2008) a/c keeps switching between fresh air intake and recirculation by itself. Can fix this?

Bro, I am driving Nissan Sylphy.
Air cond is very cold.
But sometimes when driving, it will get warmer and then switched to fresh air intake automatically.
Visited you once in the past to disconnect the switch for fresh air intake. But dont know why it will still switch to fresh air intake.
Realised it will only happen while driving. When car not moving, will not have this issue.
It gets worst when it is raining. Will keep switching to fresh air intake?
Is it something to do with thermostat?

Bro, do you do thermostat for Nissan Sylphy? If yes, can pm price + labour?

My air cond sometimes cold, sometimes not cold. When not cold, it will auto switch to fresh air intake. Sent to Nissan, they mentioned thermostat not good already.