Chart No. 2, Set Switch Circuit Test

When the ignition, cruise control and Set switches are in the On position, with the vehicle at the desired speed, vehicle speed should remain constant.
Constant speed can gradually be reduced when the Set switch is pressed and held while the vehicle is traveling at the previously set speed. The vehicle will coast to reduced speeds. When the desired speed is achieved, release the Set switch and the vehicle will remain at the new set speed.
Current flows to the control unit, cruise control Set switch and to ground.
Check ECU terminal No. 5 on 1990 models or terminal No. 17 on 1991 models, Set switch. With the Set switch in the On position, no voltage should be present. When the Set switch is in the Off position, voltage should measure approximately 12 volts.