The location of the switch varies by the furnace model, but it is typically located in the hot-air supply plenum, above the combustion chamber or heat exchanger of the furnace.Click to see full answer. Also know, how do you reset a high limit switch on a furnace? How to Reset a Furnace Limit Switch Locate your furnace’s heating duct. Locate the white limit switch. Look at each arm to identify the settings. Identify the component (setting) located in between the two arms. Set the temperature on the middle component to approximately 105 to 115 degrees Fahrenheit. Also, what causes high limit switch open? The limit switch shuts off the burner when the temperature exceeds a preset temperature. When the temperature reduces to normal, the burner will come back on. The most common reason for limits to open is a plugged filter or a dirty blower wheel. On the left are some high temperature limits used in furnaces. Keeping this in view, where is the furnace limit switch located? The limit switch is a safety control switch located on the furnace just below the plenum. If the plenum gets too hot, the limit switch shuts off the burner. It also shuts off the blower when the temperature drops to a certain level after the burner has shut off.How do I reset my furnace? How to Find My Furnace Motor Reset Button Turn off the power to the furnace at the circuit breaker. The circuit breaker is clearly marked. Lift up the blower compartment cover to access the blower wheel and blower motor. Look for a small red or yellow button on the side of the blower motor. Press the reset button down if it has popped up.