SRS light came on then cruse control doesn't work. Horn works, all fuses good, checked switch ok, no power to black box. 2 pins at switch have power and horn honked checking with test light. What next?
The most common suspect is the clock spring. That's a wound-up ribbon cable in a plastic housing under the steering wheel. To verify it, there is going to be a diagnostic fault code stored in the Air Bag Computer. A mechanic with a scanner that can access that computer can read the codes for you. With a broken clock spring, the code will be "Open initiator circuit" or "Open squib circuit", or something similar to that.
The scanner can also show the state of the cruise control switches, meaning pressed or not pressed. With a broken clock spring, none of those switches will change state when you press them.
There's multiple circuits in the ribbon cable. As it continues to break, eventually the horn will stop working too.