Step 5 · Test the Lower Thermostat

This is the step most people slow down on. Take it one move at a time — there’s no rush, and you can rewind the clip as many times as you need.

If the upper thermostat tested fine, move to the lower one. The lower thermostat is simpler, usually with only two terminals. Ensure the temperature dial is turned up. Take a photo of the wiring. Disconnect the two wires from its screw terminals. Set your multimeter to the continuity setting (Ω or sound). Touch one probe to each of the two screw terminals. You should get a reading of 0 ohms or hear a continuous beep, indicating a closed circuit. If the multimeter reads OL (Open Loop) or does not beep, the thermostat has failed and must be replaced.