park light circuit.
If it works like the one in my '94To set it: in park press the pedal to the floor.To release it press the regular break pedal and shift out of park.
Shift Cable
It prevents the starter from turning when the car is NOT in Park or Neutral, so that cars don't accidentally take of when starting.
1. Lift the shift tower cover off the center console 2. at the passenger side of the shifter & down into the center console there will be a mechanism with a small plastic arm pointing at a metal pin. 3. Swing the small plastic arm so it is no longer pointing at the pin & press the shifter button. You should now be able to freely move the shifter as normal. If you place the shifter in park again, you may have to rotate the plastic arm again if you need to select a different gear again.
Shift linkage out of adjustment?
This is commonly cause when the transmission is replaced and the shift linkage is not hooked up properly. Find the shift cable on your transmission and disconnect it, then put your shifter into park. The transmission linkage needs to be put in park as well. Now that both the transmission and your shifter are in park, you can adjust the cable accordingly and reconnect it. This should solve your problem.
linkage to transmission poped out!
I had this problem, the stick-shift was not fully in the 'park' position try and jiggle the stick.
You don't mention what year of Mercury Grand Marquis but the owners manual will explain what to do if the transmission gear shift lever will not shift out of ( P / PARK ) with the brake pedal depressed ( it has what Ford calls the " brake shift interlock " ) As of August 6 , 2012 you can still view the Mercury Grand Marquis owners manual online ( back to the 1996 model ) at : www . motorcraft service . com ( no spaces ) Click on Owner Guides
most new cars need brake pedal depressed in order to take the car out of park
In my experience , my villager would not shift from park to anything. Found a T20 or T25 torx screw under dash by steering column to be really loose on shifter linkage. Works great now!