Component Tests

Speed Control Actuator Switch Assembly

Disconnect the 6-pin connector at the speed control amplifier (9D843) assembly. Refer to the wiring diagram before performing the following checks.

1. Connect a voltmeter across Circuit 151 (LB/BK) and ground. With ignition switch (11572) in the RUN position, press the ON button and check for battery voltage.

2. Connect an ohmmeter between Circuit 151 (LB/BK) and ground.

3. Rotate the steering wheel (3600) throughout its full range of motion while making the following checks.
   1. Press the OFF button and check for a reading between 0 and 1 ohm.
   2. Press the SET/ACCEL button and check for a reading between 714 and 646 ohms.
   3. Press the COAST button and check for a reading between 126 and 114 ohms.
   4. Press 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 (14A664) as follows.

4. 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.

5. Disconnect horn relay and bracket (13853). 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).

6. 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 . Refer to Section 13-06.

7. Disconnect speed control actuator switch (9C888) assembly 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 assembly connector in the steering wheel. Each resistance reading should be between 0.25 and 0.5 ohms.

8. Check continuity in Circuit 151 (LB/BK) between speed control actuator switch assembly and speed control amplifier. Check continuity to ground in Circuit 57 (BK).

   Reconnect the 6-pin connector at the speed control amplifier .

    CAUTION: Do not use a test lamp to perform the following tests as excessive current draw will damage electronic components inside the speed control amplifier . Use only a voltmeter of 5,000 ohm/volt rating or higher.

ON Circuit

Turn ignition switch to RUN. Connect voltmeter between Circuit 296 (W/P) and ground in 6-pin connector at speed control amplifier . Voltmeter should read battery voltage.

If battery voltage is not present, check the fuse and service as required.

Connect voltmeter between Circuit 151 (LB/BK), and ground in 6-pin connector at speed control amplifier . 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 speed control amplifier (either black wire on the 6-pin connector). If there is still no ground on the speed control amplifier , check the system ground connection, and wiring. Also check the 20-amp fuse and/or substitute (but do not install) a known good speed control amplifier 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 6-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 speed control amplifier 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 6-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 6-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 6-pin connector and ground, press and hold the RESUME button on the steering wheel. The voltmeter should read approximately 6.5 volts.