A series of resistors controls the speed of your Expedition’s blower. At high speed, resistors are bypassed and a full 12.6 volts are sent directly to the blower motor. At lower speeds — medium 2, medium 1 and low — the voltage is dropped accordingly across the resistors. If the blower isn’t working at all – even on high — then chances are the blower motor has failed. There are some tests to run, to make sure the problem doesn’t lie in the blower motor circuit or in the control panel itself. The following procedures are based on a 2011 Expedition, however, other years are similar.
Items you will need: Flat-head screwdriver, Fused test lead wires with female blade connectors on one end and eyelet connectors on the other, Multimeter, Socket set, Ratchet
Testing the Blower Motor
Access the blower motor