I have a 90 GMC 3/4T Suburban 4x4 and the brake light on the dash keeps coming on. I've replaced the front rotors/pads, and master cylinder, the rear brakes are good. I have been removing the switch and reinstalling at the proportioning valve and resetting the computer, but this only lasts about a day. I thought the master cylinder would've taken care of it and I am fresh out of ideas. Any thoughts would be appreciated.
Thanks,
Rick

Check the e-brake switch?:confused:

I have the same problem & the same truck but I m not sure of the
3/4 because I have (2500)
any body can.....sos....!!!
one more thing rick do you use any type of (diff locker) if you have.
could you tell me pleas which one or the part no
my front diff is (10) bolt & the rear is semi-floating (14)bolt.
my regard.
E MAIL( binjabr7@hotmail.com )