One problem related to underhood wiring has been reported for the 1999 Mercury Mountaineer. The most recently reported issues are listed below.
Have been having touble with door locks, delay switch on rearview mirrow, window lock and window functions, abs on all the time ,door ajar light on all the time. Nonfunctioning dome light switches and intermittant check engine light ( which when checked was determined to be some unkown insuficiant exuast flow issue). Constant clicking noises coming from the far left drivers side of dash. We noticed a flame coming out of my left front top dash vent after car had been parked for 5+ hours. It's obvious the fire started in the dash and it burnt both of the wiring harnesses under the left front control panel hitting the vent line and coming out the top vent of the drivers side of the dash. We had to poor buckets of water inside dash vents/ openings and front hood area to get the flames out. Our injuies were incurred while trying to put out the fire.