2003 Ford Expedition eddie bauer 5.4L V8. AC started cutting out. It would be blowing cold good air in front and then just stop blowing. When I would hit a bump it would turn on sometimes and then back off. Seems like it hasn't come back on in awhile. Curious if this would be the Blower Resistor, or the Blower Motor or a short somewhere. I opened it up and jiggled the harness around with the AC on and it didn't turn on. The back AC blows fine and cold. Please help. Thank you.

 

Probably a blower motor with worn out brushes.

There are voltage checks that can be made, if you have both the capability and the inclination, which can pinpoint the fault.

 

I have a multimeter. Can you tell me what do I check for voltage and how?

 

There are multiple things to check, so hang on. Do them IN ORDER. If a step fails, STOP, do not skip forward.

Check fuse F116 in the Central Junction Box. ALWAYS HOT. Check both test pins with your meter.

Identify the front blower relay in the CJB. Ignition to RUN. Turn the climate control switch (assuming manual) between OFF and any other position. You should be able to either feel or hear the relay click with each on/off transition. If none, check fuse F13 in CJB.

Locate the two wires that feed the blower motor (passenger side, up under the dash). Backprobe connector to make readings. Ignition in RUN, climate control mode switch in any position except OFF, blower speed control to HIGH/MAX. You have to do this when the blower is NOT function as it should.

Brown/Yellow wire should be battery voltage (via relay and F116).
Orange/Black wire should be zero volts.

Report results for further analysis if needed.

 

Turn the blower on and give it a rap with a hammer to see if it starts. If it does the motor is worn.

 

That would be the shortcut.