Liberty, Wrangler 2006-2007

Electric Fan Switch



  1. Turn the ignition OFF .
  3. Remove the relay.
  5. Locate the 2 terminals on the relay, which are connected to the coil windings. Check the relay coil for continuity. Connect the common meter lead to terminal 85 and positive meter lead to terminal 86. There should be continuity. If not, replace the relay.

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    Fig. Use an ohmmeter to check for circuit continuity of the coil in the relay

  7. Check the operation of the internal relay contacts.
    1. Connect the meter leads to terminals 30 and 87. Meter polarity does not matter for this step.
    3. Apply positive battery voltage to terminal 86 and ground to terminal 85. The relay should click as the contacts are drawn toward the coil and the meter should indicate continuity. Replace the relay if your results are different.


If the relay functions properly during this test, inspect the coolant temperature sensor and the cooling fan system wiring for defects.

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Fig. Terminal identification of the most common types of relays. Diodes and resistors in the relay prevent voltage spikes induced when the current is removed from the coil from damaging electronic components