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Pinpoint Test A - System Inoperative

  1. Check Power To Servo Unplug harness connector from servo. Turn ignition on. Using DVOM, measure voltage between pins No. 7 and 10 of servo connector. If battery voltage exists, go to step 3). If battery voltage does not exist, check for battery voltage between pin No. 7 and chassis ground. If battery voltage exists, go to next step. If battery voltage does not exist, check or circuit for open. Repair or replace as necessary.
  2. Check Module Ground Measure resistance between pin No. 10 and chassis ground. If resistance is less than one ohm, repeat step 1). If resistance is greater than one ohm, repair ground circuit.
  3. Check Deactivator Switch Circuit With brake released, measure voltage between pins No. 9 and 10 of servo connector. If battery voltage exists, go to step 5). If battery voltage does not exist, unplug connector from deactivator switch, located at the brake proportioning valve on vehicles with ABS, or junction block below brake booster on vehicles without ABS. Measure resistance between both pins of switch. If resistance is less than one ohm, go to next step. If resistance is greater than one ohm, replace deactivator switch.
  4. Check Power To Deactivator Switch Measure voltage between circuit No. 10 (Light Green/Red wire) of deactivator switch and ground. If battery voltage does not exist, check for blown fuse or open in circuit. If battery voltage exists, measure resistance on circuit No. 636 (Orange wire) between deactivator switch and servo. If resistance is less than one ohm, repeat step No. 3). If resistance is greater than one ohm, repair open circuit in wiring.
  5. Check Brake Switch Measure voltage between pins No. 4 and 10 of servo connector. If battery voltage exists, replace brake switch. If battery voltage does not exist, go to next step.
  6. Measure resistance between pins No. 4 and 10 of servo. If resistance is greater than 10 ohms, replace brakelight bulbs or repair brakelight circuit. If resistance is less than 10 ohms, go to next step.
  7. Check For Stuck ON Switch Measure voltage between pins No. 5 and 10 of servo connector. If battery voltage exists, replace ON switch. If battery voltage does not exist, press ON switch and measure voltage between pins No. 5 and 10 of servo connector. If battery voltage is present, go to step No. 9). If battery voltage does not exist, go to next step.
  8. Check For Open In ON Switch Ground With horn button pressed, measure voltage between pin No. 6 of servo connector and chassis ground. If battery voltage exists, replace ON switch. If battery voltage does not exist, check for blown fuse, faulty relay, or open switch ground circuit.
  9. Check For Stuck SET/ACCEL Switches To check for stuck SET/ACCEL switches, measure resistance between pins No. 5 and 6 of servo connector. If resistance is less than 3000 ohms, replace faulty SET/ACCEL switch. If resistance is greater than 3000 ohms, press SET/ACCEL switch and measure resistance between pins No. 5 and 6 of servo connector. If resistance is not 646-714 ohms, replace SET/ACCEL switch. If resistance is 646-714 ohms, go to next step.
  10. Check Vehicle Speed Sensor (VSS) Circuit To check VSS circuit, measure resistance between pins No. 3 and 10 of servo connector. If resistance is 200-300 ohms, go to next step. If resistance is not 200-300 ohms, unplug VSS connector, located at left rear of transmission. Measure resistance between VSS terminals. If resistance is not 200-300 ohms, replace VSS. If resistance is 200-300 ohms, check for open or short in circuit.
  11. Check For Broken Or Binding Servo Cable Remove servo cable from servo. Check for broken or binding cable by pulling on cable ball slug. Replace cable as necessary. If cable is okay, replace servo.
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