Chart No. 5, Vehicle Speed Sensor Circuit Test

With the main cruise control switch in the ON position, turn the Set switch to the ON position and set desired speed. The control unit sends current to the electromagnetic clutch coil of the actuator. This attracts the clutch plate and illuminates the "Cruise" indicator light. When the ring gear of the planetary pinion is secured, the control unit causes the DC motor to be switched On.
Rotation of the DC motor is transmitted to the worm gear, then to the worm wheel, the sun gear, and the planetary pinion. Because the ring gear is secured at this time, the planetary pinion rotates while revolving around the sun gear. Because the planetary pinion is installed into the carrier, the carrier and the selector driveshaft unified with it, as well as the selector, are caused to rotate.
The change in direction of rotation of the selector, regulated by the control unit, is accomplished by reversing the direction of current flow to the motor.
The current flow to the electromagnetic clutch is interrupted if the main switch is turned off, or if cruise control system operation is cancelled by an input signal to the control unit. Some examples of input signals which would cancel cruise control system operation are, activation of the stop light switch, clutch switch, or the inhibitor switch.
As a result of this interruption, the clutch plate returns from the electromagnetic clutch side to the ring gear side due to the force of the spring. The ring gear then becomes free.
When the ring gear becomes free, the planetary pinion releases from the sun gear, releasing the selector to its original position.
With the cruise control main switch is in the ON position measure voltage at terminal 8, testing the electromagnetic clutch coil transistor. Voltage should measure 0 volts.
During acceleration by use of the Resume switch, measure voltage at terminal 9, testing the DC motor drive (Pull side). Voltage should measure 0 volts.
During speed reduction by use of the Set switch, measure voltage at terminal 9, testing the DC motor drive (Rel side). Voltage should measure 12 volts.
During acceleration by use of the Resume switch, measure voltage at terminal 20, testing the DC motor drive (Pull side). Voltage should measure 12 volts.
During speed reduction by use of the Set switch, measure voltage at terminal 20, testing the DC motor drive (Rel side). Voltage should measure 0 volts.