I had my steering wheel controls replaced because the ones on the left were lose. The dealer replaced the controls on both sides of the steering wheel. I tested to make sure all of the buttons work. I am not sure of my speed when I tried but the set light would not stop blinking. The on button worked but the set button did not seem to work. When I called the dealer, they said that I had to be going atleast 45 mph for it to work. Well, I looked in them manual and it shows that cruise control should work from 25mph to 89mph. I know I was going over 25 when I tried but not sure about 45. I will try that when I go home tonight.
I have a 2005 QX56. Does anybody know the real minimum speed for cruise control to work?
Thanks all of you knowledgeable people.

I set it for 25mph in School Zones all the time. When I see a Cop sitting there, I set it at 25mph then decelerate to 20mph. I've played with it in the neighborhood and can't get it to set at anything below 25mph but I can set it and decelerate to 5mph and it still works. Anything below 5mph requires hitting the Cancel button.

I always play with the cruise before adding larger tires because the Speedo gets wrong a little and that Cruise Control is my only savior from getting a ticket. Right now, I'm moving about 2mph faster than my Speedo reads. ;)

Thanks Pops, I am going to have to call back the dealer and have them make sure my cruise control works down to 25.

I would have them make sure it 'SET's at 25mph and 'works' down to at least 20mph when decelerating then you should be good to go.

Mine sets at 25 also. I think every vehicle I ever had w/CC would set at the minimum of 25 mph!

Thanks BlakSpyda

the set light would not stop blinking. The on button worked but the set button did not seem to work. When I called the dealer, they said that I had to be going atleast 45 mph for it to work.

I know this is an old post, but I was looking for answers because I am periodically having the same problem. It seems to go away after I turn the car COMPLETELY OFF, then it works no problem. I haven't been able to recreate the blinking light to see what causes it. Like I said before, it seems to happen randomly.