The air pressure switch receives power on one side of terminal once fan contact is energized and fan is running. The dryer must be full of grain to create required air pressure to satisfy switch.
- If light is not ON and fan is running, check to make sure that adjustment on switch is all that might be needed to energize air pressure light.
- If adjustment is not enough to energize switch, then check air pressure light by jumping terminal at air pressure switch. If light does not come on check wiring to switch and to light. Does light work when energized?
- Disconnect wires from switch and unscrew switch from tube. While fan is running can you feel air from chamber coming out of tube port? If not clean out tube and/or clean off filter inside chamber on opposite end of tube.
- If air is feeding into switch and air pressure switch is not making and one side of terminal is 120 volts, then make sure opening on switch has plug with small orifice to create low pressure side. Make sure nothing is internally wrong with diaphragm. Make sure diaphragm is not frozen solid. Replace air pressure switch.