Shut off the power supply to start, open the cabnit and look under the unit there should be a resess in the center where you can fit an allen wrench into and turn to check for debris in the unit. Work it back and forth to loosen any possible abstruction. Turn the power back on and try the switch if this doesnt work you need to remove the trap from the drain underneath the sink. Its a U shape piece of pipe that catches debris in it and prevents sewer gas from entering the home.
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Shut off the power supply to start, open the cabnit and look under the unit there should be a resess in the center where you can fit an allen wrench into and turn to check for debris in the unit. Work it back and forth to loosen any possible abstruction. Turn the power back on and try the switch if this doesnt work you need to remove the trap from the drain underneath the sink. Its a U shape piece of pipe that catches debris in it and prevents sewer gas from entering the home.