The parking brakes are inside the back of the rear rotors. If you have never done a brake job before i do suggest that you take the car to a qualified tech. Could save some one Else's life. However, once the car in up on blocks, remove the wheels, remove caliper, and if the rotor does not pull off easily then you will have to slack the parking brake enough so that the rotor does pull off. The rest of the work is as a regular brake job, just that the parts a smaller.
change the brake lights check the fuse check the brake light swtch
A lubricant on your 1995 Ford Mercury emergency brake can help to get it unstuck. Tapping on the emergency brake with a rubber mallet might also help.
DOT 3
According to the 1996 Mercury Grand Marquis Owner Guide : ( DOT 3 brake fluid , meeting Ford specification ESA-M6C25-A )
'P'arking or emergency brake
The fuse box is under the dash on the driver's side. It is need the emergency brake, it should have a black cover on it. You have to kneel down to find it.
Your Brake Lights. It's mounted on the Steering Column and is very easy to change. Around $10 at your local parts store.
In a 1998 Mercury Grand Marquis ( fuse # 16 is a 20 amp fuse for the cigarette lighter and emergency flasher relay ) in the fuse box below and to the left of the steering wheel , by the brake pedal ( it has a cover on it )
Why ? Just replace it.
I don't know where it is loose, get a manual on your car.
According to the 2001 Mercury Grand Marquis owners manual the fuse panel is below and to the left of the steering wheel , by the brake pedal , and has a cover on it
Upper most left 20 amp fuse in fuse box, located above emergency brake pedal. Also controls emergency flashers according to Mercury manual. Should be extra 20 amp fuse and fuse puller on fuse box cover.