Ok, so last night, on my way home, I noticed that I had little to no brake pedal, all the way on the floor and my Jeep was still creeping along. BRAKE light on the instrument cluster stays lit, and beeps all the time. Fluid was good, brake pads fine, bleeder valves are all tight, no leaks that I have noticed in the parking lot, or in the garage AT ALL..... Any ideas?

Your parking brake was/is on. The BRAKE light the instrument cluster comes on only when you set the parking brake as far as I know. Driving, the rear brakes got really hot, the brake fluid boiled, and your pedal got really mushy. Did the pedal feel harder this morning?

That's probable. But I have never used the parking brake. It turns out that the master cylinder had air in it. I bled it this afternoon, and everything is fine now. As far as the instrument cluster, I have heard that it will come on and beep if you're low on fluid as well. Oh well, another lesson learned I guess. Thanks.

ya, the light comes on when the pressure is low also, its odd for a master to get air in it for no reason, you may have a master on its way out.

Your situation bothers me....a lot.
IF your brakes were relatively good, then you suddendly had no pedal because you found air in the Master cylinder. Bleeding it out is fine BUTThe question now is :WHY WAS THERE AIR IN THE MASTER CYL. AND HOW DID IT SUDDENLY GET THERE?? more importantly, what is stopping it from happening again and soon, like right before you need those brakes again?????

Unless you had done something to the brakes right before their failure, I strongly suspect you may have more problems...your description of the problem makes me think you have an internal seal in that mastercyliner leaking, and if that is right, you will loose your brakes again.....I hope I am totally wrong here, but I would pull that master cylinder and rebuild or replace it NOW. What have you got to loose even if it doesn't need it? Good luck!

Wow! Well let's just hope that bleeding it took care of it. I changed the brake pads a few weeks ago and when my father in law was helping me bleed them, he broke the bleeder valve. We bled all the other ones and left that one until the next day, stupid I know, but it's in the past. When we got the valve changed, we bled just the rear. And if I'm not mistaken, I don't remember checking the fluid level when we bled them that time. So it's possible that the air got in at that time. So far, I've got my pedal back and no more problems. *Fingers are crossed* Thanks for the input

is there a reason you were bleeding the brakes for just changing the pads, or did you do more work?

For sure, if you were bleeding the brakes and let the fluid level drop too low in the master cyclinder and did not top it up, then that is where the air came from...cool.
If you went back and blead them all again while keeping the MC filled in the process then I think you're good to go. Can't hurt to keep an extra eye on things for a day or two...have fun!