Brake light problem, not coming on sometimes.

Have a 1995 CH Tractor and the brake lights are Not coming on sometimes, I replaced the switch by the pedal but still it appears to be random regardless if I try the Hand brake or even pull my parking brake out the lights may come on or not.. Kind a like they are getting power some of the time. I all so replaced the relay fuse for the brakes but that didn't seem to solve the problem either. then I tried jiggling the turn signal back and forth , nothing, but I noticed if I JAB on the brake pedal HARD or the hand valve the brake lights work, but if I just do it like normal they will not come on.. I checked the air flow at the switch and it blows fine..?? got me puzzled. I even replaced the new switch to see if that was it but nothing..

Any ideas