My brakes are locking up

I own a 94’ Mercury Villager minivan with over 165,000 miles. I have a problem that I’m hoping someone can help me with. My front driver-side disc brake locks-up when I apply firm steady pressure to the brakes. I then need to let the car sit for hours before the brake finally releases. It only affects the one. I noticed that if I pump the brake once, and then apply steady pressure, I have all the braking power I need and the brake does not lock-up. One last thing, the “brake warning light” stays on from the time I start it up until I shut it off. What could be the cause?

If the brake fluid level is low the brake warning light will stay on. Check the brake fluid level. As far as the left front brake locking up and not releasing, the next time this happens remove that tire and open up the bleed screw on that caliper. If brake fluid squirts out of the bleed screw, it could mean the flexible rubber brake line to that caliper has collapsed internally, and the rubber inside the hose is acting like a check valve. That is, it’s allowing the hydraulic pressure of the brake fluid to be applied to the piston when the brakes are applied, but not allowing the hydraulic pressure to be released when the brake pedal is released.

Tester