1. The Set Cruise feature requires the operator to set the initial set speed by using the set/coast button before the resume/accel slider switch input will be recognized whenever the cruise is turned OFF or the ignition switch is closed.
2. The Brake Cruise feature requires the cruise module to see terminal D change states once each ignition cycle before allowing the cruise control to operate. Some cruise modules will use either D or G.
3. Verify that the cruise control module linkage is connected and moving freely.
4. Inspect the cruise cable adjustment. Refer to Cruise Control Cable Adjustment .
5. Verify that CKT 17, CKT 1320 and the stoplamps are working properly. If the components are inoperative, the cruise control module will be disabled.
6. The cruise performance can be affected by trailer towing and steep grades.

Gasoline Engines

The cruise control module contains a stepper motor. The stepper motor positions a cable connected to the throttle. The cruise control cable operates the throttle in the same manner that the accelerator cable does. The cruise control cable is wound on a reel in the module, the stepper motor turns the reel in 1 direction or another in order to control the position of the throttle and the vehicle speed. When the cruise control system is idle or disabled, the stepper motor is disengaged. The cable is free to move in accordance with motion of the accelerator cable. When the cruise control is ON , the stepper motor will engage the cable. The stepper motor will position the cable in order to maintain a minimum speed. The use of the accelerator to increase speed is permitted, but the release of the accelerator will not decrease the speed to less than the speed set by the cruise control module. The cruise control system will not limit the speed when the vehicle coasts down a hill.

The cruise control module is powered with the ignition switch in the RUN position by the cruise fuse through CKT 41 (BRN). This fuse also provides voltage for the cruise control switch. The cruise control switch is on the steering column in the multifunction lever. The cruise control module is grounded by CKT 451 (BLK/WHT) at ground G103.

The cruise control switch consists of 2 switches. The cruise control switch provides 3 separate inputs to the cruise control module. The cruise control switch consists of a set/cruise (S/C) push-button and a 3 position OFF-ON-R/A slider switch. With this switch in the ON position, CKT 397 (GRY) sends a signal to the cruise control module. The signal enables the cruise control module response to the other 2 switch inputs. Placing the switch in the OFF position while the cruise control is engaged will disengage the cruise control system with out retaining the speed setpoint memory.

CKT 84 (DK BLU) delivers he S/C push-button input. The push-button input must be present in order to initially engage the cruise control. With the cruise control not yet engaged, the push-button input sets the speed at which the cruise control module will operate until the module is otherwise directed. Once the cruise control is initially engaged, 2 other functions can use the same set input. If the S/C push-button is pressed for a short time , the input will cause the cruise control module to tap-down the speed setpoint by 1.6 km/h (1 mph). You can perform repeated tap-down operations as long as the vehicle speed remains above the lower limit for the cruise control operation. The cruise control will not engage with vehicle speeds lower than 40 km/h (25 mph). If the push-button is pressed for a longer period of time, the cruise control module will disengage the throttle. The cruise control module will wait for the push-button to be released and the vehicle will coast. When the push-button is released, the cruise control module will reengage with the current speed as the control setpoint.

CKT 87 (GRY/BLK) provides the resume/accelerate (R/A) input. The switch input has 3 functions. If the cruise control was operating and then disengaged by the actuation of the brake pedal, this input will cause the cruise control module to resume operations at the previous set speed setpoint. If the engine has been turned OFF or the cruise control switch has been placed in the OFF position since the previous operation, no response will occur. If the switch is actuated for a longer period of time, the cruise control module will increase the vehicle speed (accelerate) until the switch is released. When the switch is released, the current speed becomes the new speed setpoint.

The cruise control module monitors 2 stoplamp switch inputs, 1 is normally closed, terminals D and C, the other is normally open, terminals A and B. Voltage is supplied to the stoplamp switch pin D from the BRAKE fuse. The stoplamp switch sends an enable signal to the cruise control module through CKT 420 (PPL) and CKT 379 (BRN/WHT). With the brake pedal released, the signal is present. When the signal is present, the cruise control operations may be engaged. The loss of the voltage, as when the brake pedal is depressed, will cause the cruise control module to disengage. The cruise control module retains the previous speed setpoint information in the event the operations are resumed. Intermittent opens or shorts to ground on CKT 420 (PPL) or CKT 379 (BRN/WHT) will also cause the cruise control to disengage.

The other stoplamp switch input on CKT 17 (WHT) and CKT 379 (BRN/WHT) is used to test the stoplamp switch operation before engaging the cruise control. After the ignition switch is placed in RUN, you must depress the brake pedal in order to provide cruise input through CKT 17 (WHT) and CKT 379 (BRN/WHT. After the stoplamp switch operation is confirmed, the cruise control module will respond to a set input.