Brake lights stay all time - 2005 GMC Sierra 2500HD 4WD

Your post gives the year of the truck as a 1993 and 1985...
The light on the dash may be your parking brake.

have alternator out put checked with engine running should be 13.5 - 14.5 volts.if alternator not faulty could have bad wheel speed sensor or wheel bearing failing.

pull the breck release and kick it at the same time same thing i had to do hey it worked for me

Check your brake switch as it could be faulty hence causing a close circuit which in turn causes the brake light to stay on.It is normally located at the top of the brake pedal.Hope this helps.

The brake light switch is located is located under the
dash, at top of the brake peddle.
To test the sw, use a 12v test light check for constant power out of the switch, with nothing else on. If there's pwr. out replace the switch.
Hope this helps. Good luck

I had a similar problem like this with my 98 explorer once; neither brake lights worked and the top one stayed on very dimly at all times. It turns out both of my brake lights went bad at exactly the same time, which for some reason made the top light stay on. Felt like an idiot, but all I needed to do was change the bulbs.

CHECK BRAKE LIGHT SWITCH UNDER STEERING WHEEL TOWARD BASE OF BRAKE PEDAL.

2007 PONTIAC G6 CONVERT. BRAKE LIGHTS STAY ON WHILE DRIVING AND GO OFF WHEN PUT BRAKES ON, AND YOU CRUISE CONTROL WILL NOT WORK WHILE BRAKE LIGHTS ARE ON.

under the dashboard on the drivers side. look at the brake pedal lever. there should be a switch attached. push switch in and twist to remove. then pull the button as far out as it will go. while holding brake pedal down reinstall switch. then pull pedal up to top. this will reset the brake light switch. if they stay on still, then just replace the brake light switch.

you might have a bad brake light switch try replacing the switch