I have no brake lights I need to fix it

I thoroughly cleaned several ground contact points and re-insulated some suspect connections. Replaced brake fluid with new and flushed and bled the entire system.
Brake pedal was at top and brake lights work great. Until? I started the vehicle and the brake pedal went to the floor. I now have to do 3 quick bursts on the brake pedal and hold and the brake lights work properly. Shortly after doing this, the brake pedal seems to seep down and the brake lights go out.
I am tempted to believe there is a vacuum leak. With this said, I will be replacing the master cylinder and power brake booster with new check valve. And keeping fingers crossed.
Any suggestions are helpful.
Thanks

I have a 1194 Chevy Silverado 1500. I am having trouble getting the brake lights to function. All of the running lights work, blinkers and back up lights also. I have replaced the fuse, the lights themselves, and the switch behind the brake pedal. What do I need to work at next?

Yes. It does have a high mount brake light and cargo light. All the bulbs have been replaced in that light as well, and it does not work either.

Got it. While looking for the problem, I found a ground issue from an old set of backup lights that had been installed and then taken out. Found and fixed! Thanks tremendously for the help!

The brake lights on my truck stopped working. I changed out the brake switch it worked for about 5 minutes and the brakes stopped working once again. I have checked all the ground wires and they are fine I am not sure what else to do. All the fuses are good and the light bulbs are also working. What do I need to change to make the brake lights to work again?

OK thank you the 3rd brake light does work and I will check everything else.

I press the brake pedal and it blows out fuse. I replaced switch, relay and ground wire.

Added a new brake switch as soon as you press panel it blows out stop fuse.

If that does not work?

This truck is my daily and I need brake lights to drive it.

Every light but brake lights work, even running lights in the rear when the headlight switch is on. I replace the circuit boards and bulbs when I had this problem when I bought it and it fixed it for a while, until today. My brake lights stopped working and my CEL came on showing P0172 and P0175 which i've also had before but neglected to fix because the CEL went off after 50-100 miles of driving. I don't think the 2 are related but I could be wrong, please tell me if I am.

I have checked fuses, relays, grounds, and connections to the circuit boards, I even tested continuity to the brand new circuit boards as well. Does anyone have an idea of what this could be? I'm not worried about the codes right now if they don't relate to the brake light issue. I just need them to work so I can work, lol. Edit: if it matters my temperature gauge doesn't "work" either. It moves but not to where it's supposed to.

I had the same problem... It’s gonna be your hardness you’re gonna have to replace it. There not expensive and it’s pretty easy to replace. You should give that a shot. And if that’s not the problem you can always return it but I’m almost 100% that’s the issue. If you give that a shot. Let me know how it goes. Best of luck...