Road Test

Fig. 1 Cruise control troubleshooting chart:

Perform the following road test and note system operation. If system fails to operate as outlined, refer to the troubleshooting chart, Fig. 1. Inspect components as outlined in troubleshooting chart and perform necessary repairs. If a cause for the observed malfunction cannot be determined by following troubleshooting procedures, proceed to System Diagnosis.
If a condition of unwanted 3---2 downshifts exists on 1982---84 models during cruise control operation, the servo unit linkage could be improperly adjusted. Road test vehicle. If the transmission shift points are normal with cruise control off, and incorrect with cruise control engaged, add a slight amount of slack (one or two beads or holes) to the servo unit linkage. After adjusting servo unit linkage, ensure throttle position does not exceed 60° at any time after resume is engaged at 35 mph to a previously set speed of 55 mph.



ROAD TEST
1. Place instrument panel switch in OFF position. While operating vehicle at 50 mph push engagement switch button on turn signal lever and release. System should remain inoperative.
2. Place instrument panel switch in On-AUTO position. Amber light should come on.
3. Engage system by momentarily pushing turn signal engagement switch button and releasing at 50 mph, remove foot from accelerator. Green light should come on when button is released and system is engaged. Vehicle should maintain set speed of 50 mph. Note amount, if any, by which vehicle speed differs from 50 mph speed when engaged. This is called lock-in error and can be corrected by turning screw on the servo unit solenoid valve towards the S position, reducing actual engagement speed. Turning the screw towards the F position, increases actual engagement speed.
4. Push switch and hold. Vehicle should accelerate at a controlled rate. Release switch to engage system at cruise speed of approximately 55 mph. System should now be set at a new speed and maintain set speed.
5. Depress brake pedal approximately 1-2 inch. Green light should go out confirming action of electric brake release switch and vehicle should start to reduce speed. Allow vehicle to decelerate to 45 mph.
6. Momentarily depress switch and release. Vehicle should accelerate at a controlled rate and resume previously set speed of 55 mph and maintain that speed. Green light should come on when switch is released.
7. Push switch in and hold. Green light should go out. Coast to 50 mph.
8. Release switch to engage system at 50 mph. Green light should come on and vehicle should maintain that set speed.