This implies that the problem is the switch that detect that the drivers
seat is buckeled. Take a look at the fixed buckle, there should be wire
comming out from it. Make sure the wire is properly connected.

Since this is a 2005, is it still under warranty? Remember, seat belts have
a longer warranty than other parts of the vehicle. From the 2005 warranty
guide -

"Safety Restraint Coverage

"Under your New Vehicle Limited Warranty, Safety Restraint Coverage begins
at the warranty start date and lasts for five years or 50,000 miles,
whichever occurs first. During this coverage period, Ford Motor Company or
Ford Motor Vehicle Assurance Company warrants your vehicle's safety belts
and air bag Supplemental Restraint System (SRS) against defects in
factory-supplied materials or workmanship."

You should check with your dealer, but I feel certain that the seat belt
reminder light system is part of the Safety Restraint System. If the dealer
says otherwise, I'd refer them to the warranty guide and ask to talk to the
zone representative.

Ed