Cruise Failure after RS Install

I put a Remote start into a 2002 Chevy Trailblazer and everything seems to work, but the customer says that the cruise control doesn't work now. I had them bring it back in to check for loose harnesses and so forth, but the only thing I found to be out of the ordinary was that the column shroud was missing the screws that hold it together (and I never took it off). Gave vehicle back to customer to try again and they said that the cruise worked twice and then quit working again. Everything else on the shaft works (washer fluid, wipers, blinkers), just not the cruise. I asked if they were sure they understood how to operate it and to make sure they were engaging it over 25 mph, etc.... they said they've used it a million times before.  

What gives?   Any ideas?