95 F250 Powerstroke, 212,000 miles, Problem is cruise control, brake light switch. The brake light switch will come on after the engine has warmed slightly, it will go off after engine has warmed to about half way on gage. When the truck reaches it operating temp (190 degree thermostat) it goes on and off for about 20 to 30 miles and then will go off and stay off if the air temp is above 45 or 50 degrees, if air temp is below this the brake light stays on. I have replaced brake sensor on the master cylinder 4 times, the last two operate the same as I have describe above. I replaced the speed sensor on the differential 2 months ago This problem is definitely keyed to temperature. Anyone got any ideas.