The shift interlock has failed, the most common issue is from a poor connection at the brake pedal position sensor. I t became so common the factory issued a Technical Service Bulletin on it. It can also be the solenoid or cable.
LINCOLN:1998-2002 TOWN CAR
MERCURY:1998-2002 GRAND MARQUIS
The Brake Shift Interlock may be inoperative on some vehicles, not allowing the operator to move the shift lever from the Park position. Stop Lamp operation may also be affected. This may be caused by a deformed Brake Pedal Position Switch electrical connector.
Restore Brake Pedal Position Switch operation by installing an updated electrical connector and pigtail.
Refer to the following Service procedure for details.
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