Very old hot tub.I have replaced the stepper switch and many other parts.now it stopped blowing bubbles?

Question

everything worked but last night it won"t go to the heavy bubbling or the soft bubbling.It warms the waeter it circulates but will not bubble.I replaced the stepper switch and the bushings and the two air switches.what else could it be..the motor is working fine..? thanks for your help

Answer 1

Sounds like the air pump has quit or is disconnected, or the controller is not furnishing power to it.