Cruise Control Not Working

I have a 2000 GMC Sierra on which the cruise stopped working. When I turn it on (truck is stopped), I hear a click like it is on. When I get to speed (60 mph), hit the button in the turn signal, nothing happens. I have tested continuity from the steering column to the connector at the cruise module and all switches/buttons work. Before I go out and spend $400 on a new module, is there some thing else that I can try or do to check? Is there a separate servo to change? In the repair manual, it looks like the servo and module are all in one.
Thanks

There is usally two switches on the brake pedal, one for the cruise and one for the brake lights. The cruise switch could need adjustment

Where is the cruise module located? I'm having the same problem. I have access to one off a 2000, is it the same as I'd need?

The cruise control is located on the firewall in the engine compartment on the driver side at the top. There is a plug going into it from inside the cab and another stretching across the engine to control the throttle.

Thank you very much.