[求助]Nissan, Air Conditioner Problem

professional

89, Nissan, Maxima

problem:
it has an automatic air conditioner.

When I just start the car, I press the "Auto" button, it works properly, at least the 仪表显示正常.

Then I press the "off" button to turn it off.

During driving, when I press the "Auto" button to try to turn the system on, there is no response.

What may be the possible reasons?

Thanks ahead.