One thing to check is whether the horn works. If it does not, suspect the clock spring is coming apart. That's a wound-up ribbon cable in a housing under the steering wheel. GM doesn't seem to have a real lot of trouble with theirs, but if it is breaking, the horn will stop working and the air bag light will turn on eventually.
Pull up on the brake pedal with your toes while trying to set the cruise control. If that works, the brake light switch is out-of-adjustment or has pitted contacts.
Wednesday, August 31st, 2011 AT 7:33 PM