Auto Parts: My 1990 Nissan pathfinder, stoplight switch, nissan pathfinder

Question
My brake light turned on and stayed on even though the brake is off.could my brakes be locked up? Engine runs like it's working too hard when driving especially up hills.

Answer
    When you say brake light, do you mean the one on the dash or the one on the rear of the car?  Rear light is most likely a bad stoplight switch.  Dash light is probably the switch on the proportioning valve.  Laboring engine is probably imagination trying to supply a symptom to go along with the light.  Try coasting down a hill, it should accelerate down the grade.