Possible Causes

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

Restricted orifice tube.
Open fuse 2 (5 amp), 7 (10 amp) or 9 (3 amp), located in Central Junction Box (CJB).
A/C system discharged/low charge.
A/C cycling switch.
Inoperative cooling fans.