How do you get a 1997 mercury grand marquis to start after triggering the inertia switch?
Inside the trunk, on the left (driver's side in the U.S.) near the trunk lid hinge, there is a small access hole in the lining. Inside that access hole is a red button. If it is popped up, push it back down; then turn the key on but don't start the engine yet. Check for fuel leaks before starting the engine, since the purpose of the switch is to cut off the fuel supply in case of accident. If there is no fuel leak, go ahead and try to start the engine.