Definitely try to find a simple looking switch associated with the brake pedal. If it has two wires it is easy to test. If it has four or more it can be a bit more tricky. Fixing the "obvious", that is the brake light circuit will be much easier than trying to find out why the cruise control will not shut off. Since the brake light switch probably send voltage to the bulbs via that switch and that switch possibly running a relay then starting at that switch should be easy enough. If it is two wires then you should see voltage on one side of the switch. The other side should be 0 volts or very close. Press the pedal and see what happens to the voltage. If you get 12 volts on each side the switch is ok. If you see 0 volts on each side the switch is good, and it is driving a relay somewhere via sending a ground. If you suspect the switch at this time just jumper it and see if the brake lights come on.
Myron & Deborah
08 HR Endeavor 40 SKQ
2012 Ford Edge Limited FWD 3.5L
Aluminator tow bar, Demco base plate