One problem related to warning light on has been reported for the 1999 Mercury Mountaineer. The most recently reported issues are listed below.
The air bag warning light illuminated. The vehicle was taken to the dealer who diagnosed that a wire under the driver's seat was broken. The consumer was told that as long as the light remained illuminated the air bags might not inflate in the event of a crash (part # 3l2z-14b455-aa).