In the driver's side fuse box in the car check that fuse #6 a 15 Amp fuse is OK! If it is OK the light on the Cruise Control switch should light when you press the switch to the on position.
For the cruise control to work (the set/resume switch is on the steering wheel) there is a "squib cable that is in the steering wheel that can fail (if this fails the SRS air bag light failure light may be on and or the horn may not work). The cruise control computer also gets inputs from the brake light switch (and clutch pedal on a manual transmission equipped car) if this switch is out of adjustment the cruise control will not work.
Check the fuse first and after that if the light works on the cruise control switch you need a wiring diagram to check inputs to the cruise control computer.
I have the same issue. My 2005 Honda Pilot cruise control will work once in awhile. When I bought it used it did not work and then after a year it started working for 6 months. Now, it doesnt work anymore. No big deal. Maybe I should check the fuse like pat said.