1999 Suburban C/K 1500 ABS???

Can anyone give me a idea of what's going on with my 1999 C/K 1500 Suburan? The "Brake" light turns on when reducing speed and the brake peedle becomes stiff almost not stopping the vehicle. The "Brake" light will turn off when the parking brake is engaged then released - or - if you pump the brake peedle. I'm thinking it may be a ABS problem... This problem is doesn not happen all the time and the ABS light does not come on.

If the ABS light does not come on then you probably have a faulty master cylinder,,check to see if the ABS light works ,,make sure when you turn the key on and start it that the ABS light comes on and then goes out. If the light is working Im sure it is probably your master. Check to be sure you have fluid in the master,,,might sound dumb but I have seen people ask this and then it didnt have any fluid. lol Good luck!

If the ABS light does not come on then you probably have a faulty master cylinder,,check to see if the ABS light works ,,make sure when you turn the key on and start it that the ABS light comes on and then goes out. If the light is working Im sure it is probably your master. Check to be sure you have fluid in the master,,,might sound dumb but I have seen people ask this and then it didnt have any fluid. lol Good luck!
Thanks for the info... Yea, that's what I thought at first. I checked the Master cylinder and the fluid was good. I as well checked the ABS fuse and it looked good. I'll investigate further... Thanks Jim.