I had to replace my brake switch behind the pedal and afterwards the cruise control does not engage. The brake lights work again so the new switch is good. Can it be the new switch is the problem? Did I get the wrong one for use with the cruise control?

 

Only you can answer that. Is your new switch exactly the same as the old one? Did it have the same pinout? Go back over your work and see if there is an extra wire you forgot to reconnect.