To check the brake light switch, push on the brake pedal and verify that the brake lights come on. If they don't, check the brake light fuse in the under-hood fusebox on most models and also check the brake light bulbs in both taillight assemblies, including the high-mount brake light. Locate the brake light switch at the top of the brake pedal, unplug the switch connector, and check for continuity across switch terminals A and B with an ohmmeter; there should be continuity when the brake pedal is depressed and none when it's released. If the switch doesn't operate as described, replace it by disconnecting the electrical connector from the switch, removing the locknut on the pedal side, and unscrewing the switch from the bracket, with installation being the reverse of removal. For adjustment, loosen the brake light switch locknut and back off the switch until it's not touching the brake pedal, then adjust the pushrod with pliers until the pedal height from the floor is correct, tightening the locknut securely. Screw in the brake light switch until its plunger is fully depressed, back off the switch half a turn, and tighten the locknut securely. Finally, depress the pedal with your hand and measure the pedal freeplay, ensuring it is within the specified dimensions and that the brake lights operate correctly.