Car shifts out of park without depressing the brake. Don't think the shift interlocker is the problem because it won't shift when the car is off and the key is removed.

Could be the interlock brake switch . don't guess an just replace parts . You don't know how to test , take it to someone who can .

Brake-shift interlock The brake-shift interlock feature prevents you from shifting from P(Park) unless the brake pedal is depressed (with the ignition in the On position). If you cannot move the gearshift out of P(Park) with the brake pedal depressed: 1. Turn ignition key to Off. 2. Apply the parking brake. 3. Turn ignition key to Lock and remove the key. 4. Re-insert the ignition key and turn it to Off. 5. Shift the transmission to N(Neutral). 6. Start the vehicle. If you need to use the above procedure, it is possible that a fuse has blown and your brakelamps may not be functioning. Refer to the Roadside emergencies chapter for instructions on replacing fuses.

You have a shift interlock problem . What kind of vehicle ? a mercury what ?
Shift Interlock System
The shift interlock system prevents shifting from PARK unless the brake pedal is depressed. The shift interlock system consists of a shift lock actuator mounted on the selector lever. If the ignition switch is in the RUN position, the shift lock actuator is disabled when the brake pedal is depressed.
If the selector lever will not move out of PARK with the key in the ON position and the brake pedal depressed, it will need to be unlocked manually.
Do the brake lights work ?
Visually inspect for obvious signs of mechanical and electrical damage; refer to the following chart:

Visual Inspection Chart Mechanical Electrical

• Damaged shift lock actuator
• Damaged transmission control (TC) switch
• Damaged shift interlock switch

• Failed fuse(s):
  • F20 (10A)
  • F22 (15A)
• Damaged wiring harness
• Loose or corroded connections
• Damaged shift interlock switch

Symptom Chart Condition Possible Sources Action

• Shift interlock system does not release/lock correctly

• Circuitry
• Fuse(s):
  • F20 (10A)
  • F22 (15A)
• Brake pedal position (BPP) switch
• Brake shift interlock actuator
• Brake shift interlock actuator module

• Go To Pinpoint Test A .

PINPOINT TEST A: SHIFT INTERLOCK SYSTEM DOES NOT RELEASE/LOCK CORRECTLY Test Step Result / Action to Take A1 TEST THE BRAKE LIGHTS

• Apply brake pedal and view brake lights.
• Do brake lights illuminate?

Yes
GO to A7 .

No
GO to A2 . A2 TEST FUSE F22 (15A)

• Key in OFF position.
• Check fuse: Smart Junction Box (SJB) Fuse F22 (15A).
• Is the resistance less than 5 ohms?

Yes
GO to A4 .

No
GO to A3 . A3 TEST THE CIRCUIT FOR A SHORT TO GROUND

• Key in OFF position.
• Disconnect: Brake Pedal Position (BPP) Switch.
• Measure the resistance between pin 1 and ground.
  
• Is the resistance greater than 10,000 ohms?

Yes
GO to A4 .

No
REPAIR circuit for short to ground. TEST the system for normal operation
Do

Do the brake light work? No brake lights and it won't shift out of park. Check your fuses and check for loose wires. Check your brake light switch. If that has failed, you won't be able to get out of park. The other one if the shift lock solenoid which is in the shifter assembly. The brake shift interlock switch prevents the car being shifted from park unless the brake pedal is depressed. Try to apply power/ground to the proper wires & see if it will activate.. If it does, then the problem is between the brake light switch & that solenoid. Could be the wires or the switch.Make sure the shifter cable is still held down in place at the shifter assembly & under the hood. It is the interlock switch that you hear/feel clicking.It is for the prior generation but may still apply.

Good Luck and hopefully you soon will be on the road again...;-)

porsche parts

This might work for you guy's replace the brake light switch
Easy step by step tutorial watch the video. im sure it will help.
MERCURY MARQUIS STUCK IN PARK
http://youtu.be/fgUn1TuHu-0

Yeah, all cars with automatic transmissions do. Press the brake while shifting from park.

it is called the shift interlock. Yes you can bypass this. Just take it out.

It has a brake-transaxle shift interlock. You should just push the brake in to shift, but if you have done that, and it still won't shift, with foot on the brake, push the shifter all the way into park. Sometimes they don't always go into park all the way. Also if you park on a hill, it puts pressure on the btsi, so you cant shift it. Have someone push the vehicle back, just enough to take the pressure off and it should shift. I had this happen to me with my Grand Am.

These cars have a shift interlock switch that prevents the car from being shifted out of park if you don't depress the brake. If your brake lights work, then the switch it good. It isn't uncommon that the interlock solenoid fails. The solenoid moves the lock release when you depress the brake. If you look on the side of the console you can see a notch cut out. You can put a screwdriver in there to push the interlock and shift it from park. Of course, you don't want to do this all the time so you either need to replace the interlock solenoid (last I checked they were about $150) or just defeat the solenoid with a zip tie. The only problem with the zip tie is that you don't have to depress the brake to shift it from park and it can be shifted from park even if the key is not in it. Your owners manual will have better detail and pictures of the interlock and where to put the screwdriver to manually shift it from park.

The shift interlock system prevents the shifting from PARK unless the brake pedal (2455) is depressed. The shift interlock system consists of a shift lock actuator (3Z719) mounted at the base of the steering column tube (3514). If the ignition switch (11572) is in the RUN position, the shift lock actuator is continually on unless the brake pedal is depressed. The shift lock actuator is the logical culprit. Check to see if it's getting voltage when the brake pedal is depressed. If yes: the unit is either faulty, weak or stuck. I can provide wire numbers and colors if necessary. I may need the engine size and Trans. code found on drivers door sticker. Good luck! Aoogha