Cruise Control Switch: Testing and Inspection
Speed Control Actuator SwitchesCAUTION: Do not use a test lamp to perform the following tests as excessive
current draw will damage electronic components inside the powertrain control
module (PCM). Use only a voltmeter of 5,000 ohm/volt rating or higher.
Access the 60-pin connector at the powertrain control module. Refer to the
electrical schematic before performing the following checks.
1. Connect a voltmeter across Circuit 151 (LB/BK) and ground. With ignition switch in the ON position, depress the ON button and check for battery voltage.
2. Connect an ohmmeter between Circuit 151 (LB/BK) and ground.
3. Rotate the steering wheel throughout its full range of motion while making the following checks.
a. Depress the OFF button and check for a reading between 0 and 1 ohm.
b. Depress the SET/ACCEL button and check for a reading between 714 and 646 ohms.
c. Depress the COAST button and check for a reading between 126 and 114 ohms.
d. Depress the RESUME button and check for a reading between 2310 and 2090 ohms.
If resistance values are above the allowable limits, check the air bag sliding contact as follows.
(1) Disconnect air bag sliding contact at the base of steering column. Check for battery voltage on Circuit 6 (Y/LG). If there is no battery voltage, go to Step 2, then go to Step 4, otherwise go to Step 4 directly.
(2) Disconnect horn relay and bracket. Check for battery voltage at the horn relay connector in Circuit 40 (LB/W). If there is no battery voltage, check 20A fuse, and Circuit 40 (LB/W).
(3) With the horn relay and bracket disconnected, apply 12V voltage to Pin 86 of the horn relay and bracket. Check for 12V voltage at Pin 85 of the horn relay and bracket. If the voltage at Pin 85 of the horn relay and bracket is not approximately equal to 12V, replace the horn relay and bracket.
(4) Disconnect speed control actuator switch and measure resistance across each of the air bag sliding contact windings between the air bag sliding contact connector at the base of steering column and speed control switch connector in the steering wheel. Each resistance reading should be between 0.25 and 0.5 ohms.
(5) Check continuity in Circuit 151 (LB/BK) between speed control actuator switch and speed control amplifier. Check continuity to ground in Circuit 57 (BK). ON Circuit
Turn ignition switch to RUN. Connect voltmeter between Circuit 296 (W/P) and ground in 60-pin connector at powertrain control module. Voltmeter should read battery voltage.
If battery voltage is not present, check the fuse and service as required. If the fuse is continuous, connect voltmeter between Circuit 37(Y) and ground in 24-Pin connector at constant control relay module. Voltmeter should read battery voltage.
If battery voltage is not present, check the system ground connection and wiring. Also check the wiring in Circuit 361(R) between the constant control relay module and powertrain control module and/or substitute (but do not install) a known good constant control relay module and recheck for a properly
operating ON circuit.
Connect voltmeter between Circuit 151 (LB/BK), and ground in 60-pin connector at powertrain control module bracket (PCM bracket). The voltmeter should read battery voltage when the ON switch on the steering wheel is pressed and held. If voltage is not available perform speed control actuator switch test.
Release the ON button. The voltmeter should read approximately 7.8 volts. The voltage should remain at approximately 7.8 volts until one of the speed control buttons is pressed and held. If the meter reads zero, check the ground connections on the powertrain control module. If there is still no ground on the powertrain control module, check the system ground connection, and wiring. Also check the 20-amp fuse and/or substitute (but do not install) a known good powertrain control module and recheck for a properly operating ON circuit.
OFF Circuit
With the ignition switch in RUN and the voltmeter connected between Circuit 151 (LB/BK) on the 60-pin connector and ground, press and hold the OFF switch on the steering wheel. The voltmeter should indicate zero volts. If the voltage does not drop to zero, perform speed control actuator switch test. If the switches check OK, substitute a known good powertrain control module and recheck the OFF circuit as outlined.
SET/ACCEL Circuit
With the ignition switch in RUN and the voltmeter connected between Circuit 151 (LB/BK) in the 60-pin connector and ground, press and hold the SET/ACCEL button on steering wheel. Voltmeter should indicate approximately 4.5 volts. Rotate the steering wheel back and forth and watch the voltmeter for fluctuations. If the voltage varies more than 0.5 volt, perform the speed control actuator switch test.
COAST Circuit
With the ignition switch in RUN and the voltmeter connected between Circuit 151 (LB/BK) in the 60-pin connector and ground, press and hold the COAST button on steering wheel. The voltmeter should indicate approximately 1.5 volts.
RESUME Circuit
With the ignition switch in RUN and the voltmeter connected between Circuit 151 (LB/BK) in the 60-pin connector and ground, press and hold the RESUME button on the steering wheel. The voltmeter should read approximately 6.5 volts.
If all the circuits check OK, perform the speed control servo test and substitute a known good powertrain control module. Do not substitute a good powertrain control module until the speed control servo test has been successfully completed.