American Standard 2748.328 Town Square 5' x 42" Air Bath Tub in White "whirlpool rear jets" Questions

...jets failing to jet, the two on either side of the rear left corner. sounds like maybe the jet faces are turned off. see if they turn one way or the other and they may open and spew water out for

...jets hums and I can't find an access panel. The tub is located on a platform and surrounded by ceramic tile. I do not see an access panel. I'm prepared to remove tile but would like to know where ...