Brake light

I have a 91 Legacy L that has been used gently by my mom for 14 years. She put 6000 miles on it in 14 years. I brought it back to Dallas when she decided to quit driving. The car is fixin to hit 100K and the brake light stays on. It is tyhe one associated with the emergency brake not the light that comes on when you step on the brake and a bulb is burned out. The light would stay on when I released the emergency brake when I started the car 1st thing in the morning (3 am) the light would stay on the entire way to work and sometime later in the afternoon (about 105 degrees outside a whole lot hotter inside) the light would go off. I figured it was the switch. Bought a new one and managed to get the old one out and unplugged. The first problem is the light acts about the same as before with the switch unplugged so I obviously have an intermittent short somewhere else. The second problem is the mating plug is under the carpet right by the rail for the front side passenger seat and I can't get the new switch plugged in. Do I need to remove the passenger seat to get access or is there another trick. Thanks in advance for any help. I hope to get another 150K out of this car. It runs like a charm and, except for some minor door dings, it looks pretty good for 22 years old.