Plumbing Questions? Ask a Plumber and Get Answers ASAP.
Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. First I’ll need some more info so I have a more complete picture of you situation.
I'm not clear on what type of switch you refer to. An air switch button? the switch at the pump? I assume this is a whirlpool tub. Please be more specific.
Yes you can get to the locknut that holds the switch in place from under the tub. If you haven't looked there yet you might find that the problem is a disconnected or kinked air tube not the switch button.
You're going to need a pretty big hole to be able to get in there to replace the switch but it might just be the air tube. Did you check to make sure the switch (the air tube is connected to) on the pump works?
In case you're not familiar, that button on the tub just pushes a slug of air through a 1/8" ID tube to the actual switch on the pump. To check out the switch get a piece of 1/8" ID soft plastic tubing and connect it to the switch at the pump in place of the existing tubing. Then blow in the tube and see if the switch responds. If it doesn't then that's what you need to replace. I have to leave for about an hour. If you don't have any more questions I'd appreciate a favorable rating. This thread won't go away and I'll answer related follow up questions even after you rate me favorably.
Do you have any more questions?