One problem related to alternator/generator/regulator has been reported for the 1997 Mercury Sable. The most recently reported issues are listed below.
During rainy weather, the right front tire splashes water into the engine fan belt assembly causing the fan belt to slip and squeal. The power steering pump fails to turn resulting in hard steering and loss of vehicle control, the generator fails to turn resulting in battery light illumination. The right front wheelwell baffle assembly installed by the mfg does not adequately shield the fan belt assembly from rain water intrusion. A temporary, thought inadequate fix, is to apply "belt dressing" to the fan belt. Ref complaint #551260.