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
check your brake lights if they not worhing replace fuse or brake light switch
Sounds like a bad Brake Light Switch. It's located on the steering column.
Check the fuses- Shift interlock is the same circuit as brake lights. As a temporary measure - try to turn the key to 1st (unlock) position shift to neutral to start vehicle and then shift to Drive.
Just turn the key to the first position, ( not on ) and then you will be able to shift to neutral and start the car from there. Have the fuses checked and check the shifter sensor on the brake pedal.
shift lock is malfunctioning. you can bypass it there is a little "switch" on the side of your shifter for this purpose. that should help temporarily i believe there is a sensor to tell it when to shift out of park and that when this malfunctions you're stuck in park
grand marquis
transmission no good
My car will shift when i first go but wont shift after that help
Are you putting your foot on the brake ?
Probably a bad starter solenoid.
its broken !! take it to a mechanic
Check the ignition coil on the Marquis. Check the crank sensor as well. One of these is probably bad.