View Here : How To Test A Thermostat
How To Test a Thermostat. If the furnace is completely silent, make sure the furnace has power. Check the circuit breaker and use a tester to make certain there is power at the furnace. If it has power but does not start, then the problem could be a break in the wire running from the thermostat to the furnace or with the furnace itself.
How to Test or Bypass a Thermostat. Note that the wires should be screwed to terminals marked R (red), W (white), G (green), Y (yellow), and C (common). Some thermostats have only Red and White or Red and Green connected. Make a note of which wires are connected to the terminals or, better, take a photo with your smart phone.
The thermostat should emit a clicking sound and the furnace should also make a sound. If the furnace does not make a sound, the thermostat is not sending a signal and needs to be replaced.
Set your multimeter to the ohm setting. Multimeters are used to test and measure electrical current in a circuit and can be used to test whether your thermostat is working. You can purchase a multimeter at a hardware store or online. The ohms setting is a ω symbol and can be found on most modern multimeters.
Step 1: Check your gauge. If you see your temperature gauge going into the red within the first 15 minutes of driving, your thermostat may be bad. Generally, if your vehicle is overheating within 15 minutes or so of driving it, this may be a sign that the thermostat is stuck. Step 2: Check the radiator hoses.
Before checking a thermostat, remember that it is not recommended to check a cooling system when the temperature is below 65 degrees. Listen and feel for air from the return air grill when turning ...
To view all our multimeter ranges go to http://bit.ly/1EdnDeo In this video Josh shows us how to use a multimeter to check for faults in a thermostat.
Check your temperature gauge in the car. A stuck thermostat might be to blame if your gauge marker nears the red danger zone within five to 15 minutes. Turn off your car and allow it to cool before opening the hood. Unhook your coolant reservoir if you can undo it and pour the antifreeze into a container.
A good thermostat with NC contacts should read zero resistance. A good thermostat with NO contacts should indicate infinite resistance, a reading of "OL" on the LCD. You should understand that if a thermostat passes this test, it may still be bad and need to be replaced.