Cruise Control System Ford Bronco II I

DESCRIPTION & OPERATION

Ford cruise control system consists of 4 switches ("ON-OFF", "SET-ACCEL", "COAST", and "RESUME"), a servo assembly, speed control sensor, clutch position sensor switch (M/T), amplifier, wiring harness, vacuum dump valve, necessary wiring and vacuum hoses. Vehicles equipped with diesel engines also use a vacuum reservoir with an integrated check valve.

Cruise control system switches are located on steering wheel horn pad. Amplifier is located under instrument panel, and servo assembly is mounted on intake manifold or on top of the radiator (Econoline). Speed sensor is located on the transmission.

ENGAGING & DISENGAGING SYSTEM

System is operational at all speeds over 30 MPH. When "ON-OFF" switch is moved to "ON" position and "SET-ACCEL" switch is depressed, vehicle speed will be maintained. This speed will be maintained until a new speed is set, brake pedal is depressed, clutch pedal is depressed (M/T), "ON-OFF" switch is moved to "OFF" position or hazard lights are activated.

The clutch position sensor switch (M/T) disengages speed control system, preventing engine overspeed when clutch pedal is depressed. If actual vehicle speed falls more than 10 MPH below set speed, due to system malfunction or vehicle limitation, system will automatically disengage.

DECREASING SET SPEED

To decrease set speed, apply brake or clutch and reset speed, using normal method, or depress "COAST" switch. When vehicle has slowed to desired speed, release "COAST" switch and new speed will be maintained.

INCREASING SET SPEED

To increase set speed, accelerate until desired speed is reached, then depress and release "SET-ACCEL" switch. Speed may also be increased by depressing "SET-ACCEL" switch and holding in that position while vehicle automatically increases in speed. When desired speed is reached, release "ACCEL" switch and new speed will be set into system memory.

RESUME FEATURE

When speed control system is deactivated by depressing brake pedal, clutch pedal or activating hazard lights, previously set speed may be re-established by depressing "RESUME" switch. Resume feature will not function if "ON-OFF" switch is moved to "OFF" position or vehicle speed drops below 30 MPH.

VACUUM DUMP VALVE

The vacuum dump valve provides a back-up safety feature in new cruise control systems. When brake pedal is depressed an electrical signal from brake pedal switch is sent to the amplifier to put the system in stand-by mode. In addition, the vacuum dump valve will mechanically release vacuum from the servo while brake pedal is depressed, releasing throttle control from amplifier assembly.

6.9L Diesel Engines Only

The vacuum reservoir assembly is used to provide adequate vacuum to the servo under peak demand conditions from the engine. The reservoir is located on the right side apron on Econoline models and on left side apron on "F"-series. A reverse vacuum check valve is incorporated to prevent backward vacuum flow.

Aerostar, Bronco II & Ranger

Remove cable retaining clip. Disengage throttle positioner. Set carburetor at hot idle. Pull on actuator cable near servo to take up slack. While maintaining light tension on holding cable, insert cable retaining clip and snap securely.

Vehicles With 6.9L Engine

1. Set carburetor choke to hot idle position with throttle positioner solenoid disengaged. Snap molded speed control cable over accelerator cable end fitting attached to throttle ball stud.
2. Remove adjuster retaining clip (if equipped), from adjuster mounting tab. Insert speed control actuator cable adjuster mounting tab into slot provided in accelerator cable support bracket.
3. Pull cable through adjuster until a slight tension is felt. While holding throttle cable, insert retainer clip until engagement is felt, and push downward until it locks.

BEAD CHAIN ADJUSTMENT

1. On vehicles equipped with solenoid anti-diesel valve, turn ignition switch to "OFF" position. On all vehicles, adjust bead chain to obtain .060-.125" (1.6-3.2 mm) actuator arm free travel when engine is at hot idle.
2. Adjust chain to eliminate as much slack as possible without keeping throttle lever from returning to idle. Cut off chain in excess of 4 beads.

Firmly depress brake pedal and hold in position. Push in dump valve until valve collar bottoms against retaining clip. Firmly pull brake pedal rearward. Clearance between dump valve housing and White plastic pad on brake pedal must be .05-.10" (1.27-2.54 mm) with brake pedal pulled to full rear position.

Vacuum Dump Valve Adjustment Bronco II and Ranger are shown. Other models are similar. Courtesy of Ford Motor Co. Scheme 1

All Other Models

1. Make sure brake pedal is against stop in released position. Move dump valve forward in retaining clip until 1/8" or less of valve plunger is exposed.
2. Tip of valve plunger should contact brake pedal adapter. Make sure brake pedal is against stop (released position). Depress brake pedal. If vacuum still does not release, replace dump valve.

TESTING

Note. Cruise Control Tester (Rotunda 007-00013) is available for diagnosing and testing factory installed cruise control systems. The following tests are to be performed only if Cruise Control Tester (Rotunda 007-00013) is not used.

CONTROL SWITCH TEST

Note. Horn and/or cruise control may operate intermittently if ground brush is missing.

1. Check main feed fuse and brake light fuse. Replace if necessary. Remove steering wheel cover (horn pad on Aerostar series). With ignition switch in "OFF" position, connect an ohmmeter between Dark Blue wire and Black (White/Purple and Yellow/Black on Aerostar) wire of switch connector at steering wheel. Depress "ON" switch.
2. Ohmmeter should read 0-1 ohms. If reading is not correct, replace switch assembly. Remove steering wheel. Clean brush assembly and slip rings with solvent and lubricate. Reinstall steering wheel. Connect ohmmeter to Yellow/Blue wire and to Black wire of switch connector behind horn pad. Depress remaining switches and check resistances against table. If values are not correct, replace switch assembly. CONTROL SWITCH RESISTANCES Switch Position Ohms "OFF" 0-1 "SET ACCEL" 646-714 "COAST" 114-126 "RESUME" 2090-2310
3. With ignition off, connect a voltmeter to Yellow /Blue wire of switch connector. Turn ignition switch to "ON" or "ACC" position. Voltmeter should read about 7.8 volts. Depress "ON" switch. Voltmeter should read approximately 12.0 volts.
4. If voltages are correct, switches and wiring are okay. If either voltage reading is not correct, turn ignition off. Disconnect ground brush assembly from wiring harness and connect ohmmeter between White/Purple and Black wires at brush assembly pigtail.
5. Depress "ON" switch. Ohmmeter should read 0-1 ohms. Turn steering wheel while keeping "ON" switch depressed. Check for fluctuations in reading. Connect ohmmeter to Lt. Blue/White and Black wire at brush assembly pigtail.
6. Check for resistance values. Refer to the «CONTROL SWITCH RESISTANCES»(/ford/bronco-ii/i-1984-1990/remont/cruise-control-systems/#cruise-control-system) table. Turn steering wheel while testing and check for fluctuations. If fluctuations are noted, remove steering wheel. Clean and lubricate brushes and slip rings. If no resistances are read, replace ground brush assembly.
7. If resistances are correct and no fluctuations occur, switches and ground brushes are okay but correct voltage still is not present, perform AMPLIFIER TEST to isolate lack of voltage. If replacement of switch assembly does not produce correct results, check slip ring for shorts. If necessary, replace entire wheel assembly and retest.

1. Disconnect 6-way connector at amplifier from steering control switch. Check battery voltage at Lt. Blue/Black wire with "ON" switch depressed. Battery voltage should be available from Lt. Blue/Black wire leading from control switches.
2. Connect an ohmmeter between Lt. Blue/Black wire and ground. Check wire for continuity to ground with "OFF" switch depressed. If resistance higher than one ohm is found, wiring, slip rings or switch is at fault, or steering column may not be properly grounded.
3. To check steering column ground, connect an ohmmeter between a good body ground and steering column upper flange. Resistance should be less than 1/2 ohm. Rotate steering wheel, and check flexible coupling for resistance less than one ohm. If resistance higher than 3 ohms is noted, clean horn brush contacts and ground brush.
4. Resistance readings of less than one ohm must be obtained before performing remaining tests. With ohmmeter connected between Lt. Blue/Black wire and ground, depress and hold "SET-ACCEL" switch. Approximately 680 ohms should be indicated on ohmmeter.
5. Depress and hold "COAST" switch. Approximately 120 ohms should be indicated on ohmmeter. Depress and hold "RESUME" switch. Approximately 2200 ohms should be indicated.

1. Disconnect connector to speed sensor, and connect an ohmmeter between connector terminals of Dk. Green/White and Black wires at speed sensor end. A reading of approximately 180-250 ohms should be obtained. Zero ohms resistance indicates a shorted coil and a maximum reading indicates an open coil. Replace sensor in either case.
2. If ohmmeter reads 180 to 250 ohms and speedometer operates properly, speed sensor is probably good. A good speed sensor can be substituted in place of existing sensor to check proper operation.

1. Disconnect 6-way connector at amplifier. Connect an ohmmeter between Dk. Green/dashed Black connector terminals on Van models and Dk. Green/White and Black connector terminals at speed sensor end on all other models. A reading of about 200 ohms should be obtained.
2. A reading of zero ohms indicates a shorted coil or wiring harness. A maximum reading indicates an open coil or wiring harness. Replace sensor in either case. If reading is 200 ohms and speedometer operates properly, speed sensor is probably good. A speed sensor of known quality can be substituted in place of existing sensor to check proper operation.

SERVO ASSEMBLY TEST

1. Disconnect ball chain from carburetor (if equipped). Separate 8-way connector at amplifier, then connect an ohmmeter between Orange/Yellow wire and Gray/Black wire at connector. A resistance of 40-125 ohms should be obtained.
2. Connect ohmmeter between Orange/Yellow wire and White/Pink wire at connector. A resistance of about 60-90 ohms should be obtained. Reconnect ball chain to carburetor (if equipped). Start engine with servo-to-amplifier connector disconnected. Verify that engine vacuum exceeds 2.5 in. Hg (85 kpa).
3. Connect Orange/Yellow wire of servo to battery positive terminal. Connect White/Pink wire to ground and momentarily touch Gray/Black wire of servo to ground. Servo throttle actuator should tighten bead chain or actuator cable and open throttle.
4. Throttle should remain in that position (or SLOWLY release tension). When White/Pink wire is removed from ground, servo should release tension immediately. If servo fails any of the preceding tests, replace servo.

Scheme 2

AMPLIFIER TEST

1. Turn ignition switch to "ON" position and connect a voltmeter between White/Purple wire and ground in 6-pin connector at amplifier. Connect voltmeter between Lt. Blue/Black wire and ground at amplifier 6-pin connector.
2. Voltmeter should read battery voltage when "ON" switch is depressed and held. If voltage is not available, perform control switch test. Release "ON" switch. Voltmeter should read 7.8 volts. If meter reads zero volts, check ground (Black wire) on amplifier.
3. If there is no ground on amplifier, check system ground connection and wiring. Also check No. 1 and 6 fuses and/or temporarily install a known good amplifier and recheck for good "ON" circuit.

"ON" Circuit Test (All Except Aerostar, Bronco II & Ranger

1. Turn ignition switch to "ON" position, and connect a voltmeter between ground and Lt. Blue/Black wire at amplifier 6-way connector. Voltmeter should read 12 volts when "ON" switch in steering wheel is depressed and held. If no voltage is present, see HORN RELAY CIRCUIT TEST and CONTROL SWITCH TEST.
2. Release "ON" button. A 7.8-volt reading should remain on voltmeter, indicating "ON" circuit is engaged. If voltage does not remain, check for ground at amplifier, fuse and/or circuit breaker. Insert a known good amplifier and recheck "ON" circuit if necessary.

"OFF" Circuit Test

1. With ignition switch in "ON" position, and voltmeter connected to ground and Lt. Blue/Black wire at amplifier 6-way connector, depress "OFF" switch on steering wheel. Voltage should drop to zero, indicating "ON" circuit is de-energized.
2. If voltage does not drop to zero, perform «CONTROL SWITCH TEST»(/ford/bronco-ii/i-1984-1990/remont/cruise-control-systems/#cruise-control-system__control-switch-test) . If switches test good, install a known good amplifier and retest.

"SET-ACC" Circuit Test

1. With ignition switch in "ON" position, connect voltmeter leads to ground and to Lt. Blue/Black wire connector at amplifier. Depress "ON" switch, then hold "SET-ACC" button on steering wheel.
2. Voltmeter should read approximately 4.5 volts. Rotate steering wheel, and watch voltmeter for variation. If voltage varies more than .5 volts, perform «CONTROL SWITCH TEST»(/ford/bronco-ii/i-1984-1990/remont/cruise-control-systems/#cruise-control-system__control-switch-test) .

"COAST" Circuit Test

1. With ignition switch in "ON" position, connect voltmeter leads to ground and to Lt. Blue/Black wire connector at amplifier. Depress "ON" switch and hold down "COAST" button on steering wheel.
2. Voltmeter should read approximately 1.5 volts. If all functions check good, perform «SERVO ASSEMBLY TEST»(/ford/bronco-ii/i-1984-1990/remont/cruise-control-systems/#cruise-control-system__servo-assembly-test) . Insert a known good amplifier, and recheck system if necessary.

Note. DO NOT substitute a new amplifier until actuator coils have been tested. See SERVO ASSEMBLY TEST .

"RESUME" Circuit Test

1. With ignition switch in "ON" position, connect voltmeter leads to ground and to Lt. Blue/Black wire connector at amplifier. Depress "ON" switch and then hold "RESUME" switch. Voltmeter should indicate approximately 6.5 volts.
2. If all functions are okay, perform «SERVO ASSEMBLY TEST»(/ford/bronco-ii/i-1984-1990/remont/cruise-control-systems/#cruise-control-system__servo-assembly-test) . Insert a known good amplifier, and recheck system if necessary.

HORN RELAY CIRCUIT TEST

Note. Electrical connectors must remain connected during horn relay testing.

(All Models Except Aerostar, Bronco II & Ranger)

1. Locate Yellow/Lt. Blue wire on Bronco and "F" series Pickups and Yellow wire on "E" series Pickups at connector "X". Check for battery voltage on pin side of connector. (Scheme 1)
2. Locate Blue/Yellow stripe wire on "E" series or Dk. Blue wire on Bronco and 'F" series Pickups at connector "Y". Check for battery voltage on socket side of connector. With voltmeter still connected to socket, depress horn switch.
3. Horn should sound, and voltmeter should indicate zero volts. If voltmeter still indicates battery voltage when horn switch is depressed, check horn switch or steering column wiring for an open circuit.
4. To by-pass horn switch and check horn relay, momentarily ground Blue/Yellow wire on Vans or Dk. Blue wire on Bronco and Pickups on socket side of connector "Y".
5. If horn still does not sound, check Yellow/Green stripe wire on "E" series or Yellow/Lt. Green wire on Bronco and "F" series at connector "X" for battery voltage while relay is activated. If battery voltage is present when relay is activated, an open circuit is present between connector "X" and horn.
6. If battery voltage is present in step 1) and horn relay failed to operate in step 3), replace relay.

CLUTCH SWITCH TEST

Note. Switch operates magnetically. DO NOT use magnetized tools near switch. Use only a voltmeter of 5000 ohm/volt rating or higher to test switch. Test light will not indicate switch condition.

Vehicles With M/T

1. Make sure that clutch switch is depressed (switch closed) when clutch pedal is released, as cruise control will not operate unless this condition exists. Correct if necessary, before performing test.
2. Disconnect clutch switch connector from speed control harness connector, and connect an ohmmeter to switch connector terminals. With clutch pedal released and switch plunger depressed (switch closed), resistance should be less than 5 ohms.

BRAKE LIGHT SWITCH TEST

Note. This test should be performed whenever brake application will not disengage speed control system. On vehicles with M/T, ensure that clutch switch is working properly before performing this test.

1. Check for stop light operation with a maximum brake pedal effort of 6 lbs. (2.7 kg). Check brake pedal actuation and stop light switch if pedal effort required is excessive.
2. If stop lights operate correctly, check battery voltage at 6-way connector Black/Green wire on Vans and White/Purple stripe wire on Bronco and Pickups.
3. Depress pedal until stop lights are on, and check voltage at 6-way connector Red/Black wire on "E" series and Lt. Green wire on Bronco and "F" series Pickups. If voltage readings differ by more than 1.5 volts, high resistance exists in stop light circuit and must be corrected.
4. If stop lights do not work, check stop light switch, supply circuit, fuses and bulbs for correct operation.

1. Vacuum dump valve should be checked whenever brake application does not release speed control. Ensure that no more than 1/8" (3.2 mm) of plunger tip is extended when brake pedal is in fully released position. Disconnect vacuum hose from dump valve to servo, at servo unit. Connect hand vacuum pump to hose and pump up a vacuum.
2. If vacuum cannot be obtained, hose or dump valve leaks and should be replaced. Depress brake pedal. Vacuum should be released. If not, adjust or replace dump valve.

Diesel Engines Only

1. Locate vacuum reservoir on Left or Right fender. Disconnect vacuum hose at servo and connect a vacuum gauge with a minimum range of 0-25 in. Hg. Start engine and observe vacuum gauge.
2. Vacuum should be approximately 23 in. Hg., but not less than 20 in. Hg. If reading is not within specifications, check for leaking vacuum hose or faulty vacuum pump.
3. Turn engine off after vacuum has stabilized above 20 in. Hg. Vacuum should hold steady. After 24 hours, vacuum should be a minimum of 15 in. Hg. If vacuum fails to hold, replace vacuum reservoir.

See also:
• CONTROL SWITCH RESISTANCES
• CONTROL SWITCH TEST
• SERVO ASSEMBLY TEST