Brake Combo Valve Question/Disk Brakes on a 75

Hello, I am the new owner of a 75 CJ5 that needs a little work. First, My Jeep has front disk brakes. From what I have read, the 75 came with drums. Is this correct? 2nd, The PO removed the electrical switch on the combination (Proportioning) valve for the brakes. This is the switch that illuminates the brake light if you have a hydraulic problem. Anybody know where to get one? Thanks in advance for your responses