Shut off the Balboa at the control panel on the edge of the tub. Pull down the handle on the electrical box connected to the hot tub with a conduit. This shuts off electricity to the unit while you troubleshoot the pressure switch.
Open the service door at the base of the Balboa. Turn the handle clockwise and pull it to open. The pressure switch is in the right corner at the bottom.
Loosen and remove the two nuts on the contact bolts at the side of the switch. Slide off the looped metal connector on the end of each wire from the two contact bolts. Make a note to remember which wire attaches to which bolt.
Attach the clips on the ohmmeter wires to the two contact bolts on the pressure switch. If the ohmmeter displays a zero reading, turn the adjustment knob on the top of the switch clockwise until it clicks to the next position. If the ohmmeter does not register any reading after testing the switch at every pressure position by twisting the adjustment knob in increments, then the switch is defective and must be replaced.