Possible Causes

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

An open in circuit 1205 (BK), 364 (BK/LG), 261 (OG/BK), 371 (PK/WH), 298 (VT/OG) or 1322 (BN/WH).
A short to ground in circuit 1120 (BK/WH).
A short to voltage in circuit 1322 (BN/WH).
A/C blower relay.
Blower motor control module.
EATC module.
SJB.