How to Make Electrical Tests
Electrical tests fall into two broad categories: hot tests and cold tests.
- Hot Tests: tests made with power applied to the unit.
- Cold Tests: tests made with the unit unplugged.
Over 90% of the time, you'll be measuring three different electrical parameters: 1) continuity, 2) voltage and 3) amperage.
- Use the "Ohms" function of your multimeter to test for electrical continuity.
- All continuity tests are made with power removed from the appliance--that means having the appliance unplugged.
- The lower the ohms read on the meter, the greater the continuity.
- Most switchs, thermostats and other contacts that are supposed to be closedshould read 2 ohms or less if they have proper continuity.
- If you read something higher than this, the electrical control you're testing is probably bad and should be replaced.
- When testing for the presence of proper voltage, you're looking for either 120 volts AC or 240 volts AC, depending on the type of appliance.
- When testing for voltages at electric dryer heating elements and electric range or stove elements, you're looking for 240 volts AC.
- When testing for control voltages to solenoids, timers, etc., on washers and other 120 volts AC appliances (i.e., they do not require a 240 volt AC plug) then you're looking for 120 volts AC.
- Anything less means you have a problem somewhere in the circuit, usually an open switch or thermostat or one with poor continuity. Sometimes it could be a bad wire connection--look for burnt or discolored wires.
- Testing for amperage, or current, is another way of testing for continuity. The main difference being that amperage tests are made with power applied to the appliance and the appliance turned on. BE CAREFUL!
- You're looking for readings in the "amps" range, not the "milliamps" range.