Two problems related to battery have been reported for the 2004 Mercury Mountaineer. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Mercury Mountaineer based on all problems reported for the 2004 Mountaineer.
While driving 35-45 mph, car suddenly shut down. Check engine light and battery light came on. Loss of power steering, power brakes, acceleration. Maneuvered vehicle to nearby parking lot, waited, and then restarted the vehicle. No problem in restarting vehicle and all warning lights were off. Used cruise control prior to incident. Intermittent problem; unable to re-create for Ford dealer to diagnose. New battery was installed by Ford dealer in winter 2009.
While driving 40-45 mph and using the cruise control, car suddenly shut down. Check engine light and battery light came on. Loss of power steering, power brakes, acceleration. Was able to steer SUV to off the road but was very difficult to do so. Nearly ran off a 10 to 12 foot drop off into a drainage ditch. This has happened several times before. Car max (where we bought SUV could not duplicate the issue so they sent it to metro Ford in independence, mo and on the first time it happened replace the throttle position sensor but that did not fix the problem). The wrench and fail safe mode came on this last time but the persons repairing it indicated they found no codes for it and were unable to re-create to diagnose. From research I know this is a problem with other vehicles of this type (both the loss of electrical power and the no code found situation) but we came very close to an injury related accident because of this.