My cruise control does not work. The light comes on when I set it, but it does not engage. Checked the fuses and replaced the speed control sensor, still not working.

Check your vaccum hoses to crusie control. a fitting and or hose may be cracked. if so replace hose or jb weld cracked fitting

What speed control sensor ? Explain . Vehicle speed sensor ?
Speed Control Self-Test Diagnostics
WARNING: This test is a key on engine off (KOEO) test only that is conducted in PARK only with the emergency brake fully engaged.
NOTE: A review of the following test steps is required before carrying out the Self-Test Diagnostic procedure. After entering the diagnostic mode, the module will time out if the mandatory switch sequence is not completed within 5 seconds. If a module time out occurs, the procedure must be reinitiated.

1. Enter the Self-Test Diagnostics by pressing the speed control OFF switch while turning the ignition key ON, making sure the engine does not start and is not running. Five additional flashes at this point indicate a defective speed control actuator. Release the OFF switch.

1. Press and release the remaining switches in this sequence: ON, RESUME, COAST and SET/ACCEL (for Expedition), ON RESUME, COAST and CANCEL (for Navigator).
   The speed control indicator lamp will flash after each switch is pressed and released. Press and release each switch in the sequence immediately after the indicator light goes out for the previous switch.

1. NOTE: There will be a slight delay when the last button is pressed and released and the lamp flashes.
   A lamp flash with the last button (SET/ACCEL) or CANCEL (for Navigator) indicates that the STATIC test passed. If the lamp does not flash with the last button and there are no additional flashes of the lamp, the switches are defective.
   If the lamp does not flash with the last button, and additional flashes occur, follow the chart below for trouble codes:

1. Immediately after the STATIC test, the speed control servo does a DYNAMIC test by automatically actuating the throttle lever from 8 mm (0.315 in) to 12 mm (0.472 in) of travel from the idle position. During the DYNAMIC throttle pull, observe throttle movement to witness any binding or sticking of the speed control cable and correct connection of speed control cable to throttle lever. Make sure the throttle returns back to the idle position.

1. Return the ignition switch to the OFF position and proceed to the Symptom Chart.