Having a problem with an Infinity Spa. It has 3 pumps for 3 different "zones" connected to a Balboa M7 (53672-02 2M7P3) control pack and digital pad. When I press the "Jets 3" button there is a single audible click but nothing happens. The other 2 zones work fine. The spa heats and circulates without any other issues.

I swapped the Jets 2 & 3 plugs that go from the pumps to the control pack to confirm it was/was not a pump/motor problem. When switched Zone 3 (Jets 3 connected to Zone 2) works fine and Zone 2 (Jets 3 button connected to Zone 2) clicks with no result. Swapped back the result is consistent. All pumps and motors seem to be fine and the fuses inside the control pack test good with a continuity meter.

How can I further run down the root problem? Does the click indicate anything specific? A relay problem, power, pad/button failure, circuit board, or something else? Thank you!