If I remember correctly my exact symptom was the cruise would set sometimes and sometimes not. I could not go into diagnostics where the cruise control light would stay lit. I checked all connections and could not find the problem until I stumbled on the throttle cable tab connection breakage. That small connection did cause the cruise control to malfunction. You can check by carefully disconnecting each wire from the cable one at a time and try to enter into the diagnostic mode, it did cause my problem. Anyway can’t hurt if you have tried everything else, only takes a few minutes.A tab broken off this cable would NOT cause your cruise to not set. If you remove a wire from the throttle (or is it the idle) cable, your cruise will still set but rolling off the throttle will not cancel the cruise.