DESCRIPTION
Cruise control system components include Powertrain Control Module (PCM), cruise control switch, vehicle speed sensor, vehicle speed sensor buffer and brake and clutch release switches.
POWERTRAIN CONTROL MODULE
Powertrain Control Module (PCM) is mounted behind right side of instrument panel. Fuel control portion of the PCM maintains desired speed in response to cruise control switch commands. PCM performs system diagnostics and stores diagnostic trouble codes.
CRUISE CONTROL SWITCH
Cruise control switch, mounted on end of multifunction (turn signal) lever, controls system operational modes.
SET/COAST
To set vehicle speed, turn control switch to ON position. With vehicle speed at 25 MPH or more, press and release SET/COAST button. Vehicle will maintain set speed.
To increase speed during engaged cruise, accelerate to desired speed. Press and release SET/COAST button. Vehicle will maintain new set speed.
To decrease speed during engaged cruise, press and hold SET/COAST button. System will disengage. When vehicle has slowed to desired speed, release SET/COAST button. Vehicle will maintain new set speed.
To decrease speed by one-MPH increments during engaged cruise, tap SET/COAST button (quickly press and release button; DO NOT hold button). Vehicle speed will decrease one MPH for each tap of the button.
RESUME/ACCEL
To resume set speed after system has been disengaged by braking, momentarily engage and release RESUME/ACCEL switch. Vehicle will return to set speed. If RESUME/ACCEL switch is engaged for more than one second, vehicle will begin to accelerate. To accelerate using cruise control system, engage and hold RESUME/ACCEL switch until desired speed is reached.
To increase speed by one-MPH increments during engaged cruise, tap RESUME/ACCEL switch (quickly move to RESUME/ACCEL position and release). Vehicle speed will increase one MPH for each tap of the switch. After 10 taps, system must be reset to a new speed to continue this function.
BRAKE RELEASE SWITCHES
Brake release switches interrupt current flow to module when brakes are applied. When module receives this signal it disengages servo. Switch may be combined with brakelight switch or may be a separate redundant switch. Switches are connected in series.
CLUTCH RELEASE SWITCH
Clutch release switch interrupts current flow to module when clutch pedal is depressed. When module receives this signal it disengages servo. Switch is connected in series with brake release switches.
VEHICLE SPEED SENSOR
Vehicle speed sensor, mounted in transmission (2WD) or transfer case (4WD), generates AC voltage pulses that represent vehicle speed. AC pulses are sent to vehicle speed sensor buffer.
VEHICLE SPEED SENSOR BUFFER
Vehicle speed sensor buffer receives and conditions AC voltage pulses, then sends them to Powertrain Control Module (PCM) and speedometer. Buffer is located behind instrument panel, above glove box.
ADJUSTMENTS
Note. On all models, except "P" Series commercial van and motorhome, stoplight switch is not adjustable.
- Fully depress and hold brake pedal. Push switch through retainer and pedal bracket hole until fully seated. Clicking can be heard as switch is pushed into bracket.
- Pull pedal fully rearward against pedal stop until clicking stops. Release pedal. Pull pedal fully rearward again to ensure no clicking can be heard.
TESTING
Note. Manufacturer recommends use of Tech 1 Scan Tool for retrieving Diagnostic Trouble Codes (DTCs). Flash code diagnostics using the Malfunction Indicator Light (MIL) are also available.
If cruise control is inoperative, and SERVICE ENGINE SOON (MIL) light is on, see SELF-DIAGNOSTICS article in the ENGINE PERFORMANCE Section. If cruise control is inoperative, and no diagnostic trouble codes are stored, check for faulty cruise control switch, open wiring, or poor connections.
Cruise Control Does Not Engage
- Ensure BRAKE, STOP/HAZ, and CRUISE fuses are okay. Turn ignition switch to RUN position. Turn cruise control off. Check for battery voltage at Brown wire terminal of cruise control switch connector.
- If battery voltage is not present, repair open or poor connection in Brown wire. If battery voltage is present, turn cruise control on. Check for battery voltage at Gray wire terminal of powertrain control module. If battery voltage is present, go to next step. If battery voltage is not present, go to step 12).
- Check for battery voltage at Dark Blue wire terminal of powertrain control module connector while pressing SET/COAST switch. If battery voltage is present, go to next step. If battery voltage is not present, repair open, short to ground or poor connection in Dark Blue wire. If Dark Blue wire circuit is okay, replace cruise control switch. If battery voltage is present with SET/COAST switch released, repair short to battery voltage in Dark Blue wire.
- Check for battery voltage at Gray/Black wire terminal of powertrain control module connector. If battery voltage is present, check Gray/Black wire for a short to Dark Blue wire. If wiring is okay, replace cruise control switch.
- Check for battery voltage at Purple (A/T) or Brown/White (M/T) wire terminal of powertrain control module connector. If battery voltage is present, go to step 8). If battery voltage is not present on vehicles with manual transmission, go to next step. If battery voltage is not present on vehicles with automatic transmission go to step 7).
- Check for battery voltage at Purple wire terminal of clutch release switch connector. If battery voltage is not present, go to next step. If battery voltage is present, repair open in Brown/White wire. If Brown/White wire is okay, replace clutch release switch.
- Check for battery voltage at Brown wire terminal of brake release switch connector. If battery voltage is present, repair open in Purple wire. If Purple wire is okay, replace brake release switch. if battery voltage is not present, repair open in Brown wire.
- Check for battery voltage at Dark Blue wire terminal of powertrain control module connector. If battery voltage is not present, go to next step. If battery voltage is present, repair short to battery in Dark Blue wire. If Dark Blue wire circuit is okay, replace cruise control switch.
- Check for battery voltage at Gray/Black wire terminal of powertrain control module connector. If battery voltage is not present, go to next step. If battery voltage is present, repair short to battery in Gray/Black wire. If Gray/Black wire circuit is okay, replace cruise control switch.
- Raise and support vehicle with drive wheels off of ground. While turning drive wheels, check voltage at Brown wire terminal of powertrain control module connector.
- If voltage pulses between zero and 5 volts, replace powertrain control module. If voltage does not pulse between zero and 5 volts, or if no voltage is present, check vehicle speed sensor circuit. If any PCM trouble codes are set, see SELF-DIAGNOSTICS article in the ENGINE PERFORMANCE Section.
- Check for battery voltage at Dark Blue wire terminal of powertrain control module connector while pressing SET/COAST switch. If battery voltage is not present, go to next step. If battery voltage is present, repair short to ground, open, or poor connection in Gray wire. If Gray wire circuit is okay, replace cruise control switch.
- Check for battery voltage at Gray/Black wire terminal of powertrain control module connector while pressing RESUME/ACCEL switch. If battery voltage is not present, go to next step. If battery voltage is present, repair short between Gray/Black and Dark Blue wires. Check for poor connection at cruise control switch connector. If wire circuit and connector are okay, replace cruise control switch.
- Check for open or poor connection in Gray and Brown wires. If Gray and Brown wire circuits are okay, replace cruise control switch.
