Possible Causes

WARNING: This page is about a different car, the 2002 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.

Central Junction Box (CJB) fuse F37 (10-amp).
Central Junction Box (CJB) fuse F45 (15-amp).
Central Junction Box (CJB) fuse F47 (15-amp).
Blower motor relay.
Auxiliary blower motor.
Front auxiliary blower motor switch.
Short or open circuit.