Well, I’m happy to tell you your problem might be easily fixed.

#1 Check your brake fluid level, if it is low add fluid.

#2 Check to see if your 3rd brake light is working, if not replace the bulb. This also applies to any exterior LEDs you might have installed, if you have go back bulbs or add load resistors.

If you do both of these IMHO you will have a 98% chance of getting your cruise control back. Also, if your brake fluid is low plan on replacing your front brake pads soon.