Hm-mmh.

Not a spa expert, but I have worked a bit, many years ago, with air controls. There are 3 components: the tubing, the air-actuated switch, and the transmitter or button. It sounds like you may be say that the air-actuated switch works just fine, if you create the required air pressure by disconnecting the tubing from the transmitter, and blowing into the tubing directly.

If this is what you are saying, you probably need to
1. check the tubing where it connects to the button, for cracks or splits (that you may cover or seal when you blow through the tubing)
or
2. replace the transmitter or button, rather than the switch.