If the light is not coming on when you press the button then that is most likely a switch issue.
What I would do is go to the cruise control unit and press the button and see if you have voltage getting to the unit. If not then the switch or the clockspring is the issue.
If the light comes on but the cruise does not engage then by far the most common cause is the servo has failed. Basically this is the motor that holds the throttle cable in place and will actually move it when needed to keep the proper speed that you set.
This could be one of two reasons. Either the servo failed or the servo cable needs to be adjusted.
I am attaching both processes below on how to replace it and adjust it, plus the wiring diagram to help with this testing.
Please let us know if you have other questions.
Images (Click to enlarge)
Monday, August 2nd, 2021 AT 8:00 PM