Found this on a ranger forum...
This test is a key on engine off (KOEO) test that is only conducted in park with emergency brake fully engaged.
l Enter self-test diagnostics by depressing the speed control OFF switch while turning the ignition key on, making sure the engine does not start and is not running. The speed control indicator lamp on the instrument panel will flash once to indicate that the speed control module entered the diagnostic mode. Five additional flashes at this point indicate a defective speed control servo. Release the OFF switch.
If the ON switch is not pressed within five seconds after entering diagnostic mode, the module times out and the procedure must be started over.
Press the remaining switches in this sequence: ON, RSM (resume), CST (coast) and SET/ACCEL.
l The speed control indicator lamp will flash as each switch is pressed. Press each switch in the sequence immediately after the light goes out for the previous switch.
There will be a slight delay when the last button is pressed and the lamp flashes.
A lamp flash with the last button (SET/ACCEL) 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 switch is defective. If the lamp does not flash with the last button, and the additional flashes occur, follow the list below for trouble codes:
— 2 flashes: Brake pedal position (BPP) switch is defective, circuit is defective, or brake pedal is applied; clutch pedal position (CPP) switch is defective, circuit is defective, or clutch pedal is applied.
— 3 flashes: Brake deactivation switch is open or circuit is defective.
— 4 flashes: Vehicle speed signal is out of range or circuit is defective.
l 0.25 seconds after the static test has passed, the speed control servo will carry out a dynamic test automatically by actuating the throttle lever from 1 to 10 mm (.04 to.39 inch) 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, verify the correct connection of the speed control cable to the throttle lever, and make sure the throttle returns back to the idle position. If incorrect connection or binding or sticking of the speed control is observed, go to the Symptom Chart. If no dynamic pull occurs at the throttle body go to Pinpoint Test F.
l Return the ignition switch to the OFF position and proceed to the Symptom Chart.