You have a bad blower resistor. Let the glove box open all the way by releasing the side clips. Look on the left side of the plenum assembly and you will see a connector with 5 or 6 wires. Take out the 2, 7mm screws and replace the resistor assy with a new one. That will fix the problem.
Common Ford failure and about a $15.00 part or cheaper. Good Luck!
Tuesday, May 23rd, 2006 AT 2:40 PM