One problem related to air bag has been reported for the 2003 Mercury Mountaineer. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Mercury Mountaineer based on all problems reported for the 2003 Mountaineer.
Faulty airbags: on November 3, 2015 at approximately 0540, the side curtain (both driver side and passenger side) airbags exploded in my 2003 Mercury Mountaineer without cause while I was traveling 55 mph on a major/busy state highway. The explosion of the airbags hit me on my left side causing neck strain and temporary hearing loss to the left ear. I was the only occupant in the vehicle. I was able to safely drive to shoulder of road (I don't remember how I got there), luckily no cars were around me at the time. The explosion also caused the driver side window to fall from its casters and was unable to close window (and the passenger side rear window no longer works). The air in the curtains would not dissipate and I remember not being able to breath well. There was a chemical in the air and do to the curtains, it was difficult to get out of the car. Later in the day I took car to reynolds Ford and was told this was not covered by Ford. I also went to my pcp and was treated with prednisone and ear wash for left ear hearing loss. Later, had drivers window repaired.