Testing the Coolant Level Switch

Testing the switch in the unit is accomplished by adjusting the coolant level or alternatively by removing the expansion tank from the unit, then flipping the tank upside down or right side up (depending on the step from the procedure below).

  1. Remove the wire harness connector from the coolant level switch.

  2. Use an ohmmeter to check the continuity of the switch at the connection pins.

  3. Verify the coolant level is above the switch and check the continuity of the switch. The switch should be closed. If the tank was removed from the unit, accomplish this check with the tank upside down.

  4. Drain coolant from the expansion tank until the coolant level is well below the switch level and check continuity of the switch. The switch should be open. If the tank was removed from the unit, accomplish this check with the tank right side up.

  5. Replace the switch if it is does not close in step 3 and does not open in step 4.

Parent topic: Coolant Level Switch