Simple on/off switch. Though unusual, they do fail.
Mine, a 709P3, doesn't have the WH switch, however the switch body is the same 3/4" X 1/2" size as the 3 way pump switch. The HW switch is just 2 terminal on/off. Pump switch is 3, on/off/on.
The pump switch might be removed from front but there are 2 ears that need to be squeezed and switch pushes out. Removing panel, the switch terminals could be momentarily jumped to verify its the switch.