Just acquired 99 D2 and the cruise control will not work. Checked for cracked vacuum lines, got the dash switch to light up, and tested steering wheel switch. I have a SRS light on, is the clock-spring or rotary switch the next place to venture to? The horn does work but the volume control doesn't on the steering wheel. Just got radiator, thermostat, and lines ordered to sort the cooling system out. Just trying to get the little things fixed while i wait on parts. Thanks

 

If you're confident that there are no vacuum leaks throughout the system (most of the time this is the problem), check whether your brake lights work before you start digging into the clock spring. Failed brake switch can cause CC problems.

SRS light is often the yellow relays under the drivers and passengers seats (access from the front drivers and passengers footwell). Spray some electrical contact cleaner in the seat belt buckles as well.

 

Having LED bulbs in any of the brake lights can stop the cruise control from working.

 

This is what I found too. I like the brighter LEDs more than I would ever use cruise control so I deal with it.

 

Center brake light bulb burnt out will prevent it from working too.

 

Third brake light was out. Still no cruise. I should probably just replace all the vacuum lines and maybe throw a brake light switch in there and give it a try.

 

Could be a bad brake switch but do all your brake lights come on? Regardless, it's easy and cheap to replace... NAPA #ECH SL918 or Duralast #LU410.
Also make sure to push (not pull) the CC "set" button on the steering wheel.