Hi - did the diagnostic test on the cruise control. Found the steering wheel mounted buttons do not work. Now, it says possible causes are the rotary coupler, the switches themselves or the wiring.

My radio buttons work. Does this automatically point to the rotary coupler? Anyone have any ideas? Both the set and resume buttons were faulty. Anyway to test either the switches or coupler to determine which one is at fault? I have no air bag faults either.

Thanks!