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Home >> Lincoln >> 1995 >> Mark VIII Base >> Repair and Diagnosis >> Brakes >> Traction Control >> Anti-Lock Brake System >> Pinpoint Tests (Using Light Symptom Sequence Chart) >> Pinpoint Test A - Anti-Lock Light On With Brake Light Off

Pinpoint Test A - Anti-Lock Light On With Brake Light Off

  1. Turn ignition off. Disconnect ABS control module 55-pin connector. See COMPONENT LOCATIONS  . Connect Breakout Box (014-00322) and ABS Adapter (T90P-50-ALA). Turn ignition on. Measure voltage between breakout box test pins No. 53 and 60. If voltage is less than 10 volts, go to next step. If voltage is more than 10 volts, go to step 4).
  2. Check for continuity between breakout box pin No. 60 and ground. If continuity does not exist, repair circuit No. 651 (Black/Yellow wire). If continuity exists, go to next step.
  3. Ensure ignition is off. Check for continuity between breakout box pin No. 53 and ignition switch feed wire. See WIRING DIAGRAM  . If continuity exists, repeat step 1). If continuity does not exist, repair circuit No. 294 (White/Light Blue wire).
  4. Ensure ignition is off. Check for continuity between breakout box test pins No. 19 and 60. If continuity exists, proceed to next step. If continuity does not exist, repair circuit No. 651 (Black/Yellow wire).
  5. Turn ignition off. Connect jumper wire between breakout box test pins No. 34 and 60. Turn ignition on. Measure voltage between breakout box test pins No. 19 and 33. If voltage is less than 10 volts, go to next step. If voltage is more than 10 volts, go to step 12).
  6. Turn ignition off. Remove jumper wire from breakout box test pins No. 34 and 60. Measure resistance between breakout box test pins No. 34 and 53. If resistance is not 45-90 ohms, go to next step. If resistance is 45-90 ohms, go to step 8).
  7. Ensure ignition is off. Disconnect main power relay. See COMPONENT LOCATIONS  . Measure resistance between main power relay pins No. 85 and 86. See Fig 1 . If resistance is not 45-90 ohms, replace main power relay. If resistance is 45-90 ohms, repair circuits No. 513 (Brown/Pink wire) or No. 294 (White/Light Blue wire) or No. 599 (Pink/Light Green wire).
    Fig 1: Identifying Main Power Relay Terminals
    G90J09241
  8. Turn ignition off. Remove main power relay. Turn ignition on. Measure voltage between main power relay wiring harness connector pin No. 86 and ground. See Fig 1 . If voltage is less than 10 volts, repair circuit No. 294 (White/Light Blue wire). If voltage is more than 10 volts, go to next step.
  9. Turn ignition on. Measure voltage between main power relay wiring harness connector pin No. 87 and ground. See Fig 1 . If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair circuit No. 537 (Tan/Yellow wire).
  10. Turn ignition off. Check for continuity between breakout box test pin No. 33 and main relay wiring harness connector terminal No. 30. See Fig 1 . If continuity exists, go to next step. If continuity does not exist, repair circuit No. 532 (Orange/Yellow wire).
  11. Remove main power relay. Connect relay pin No. 85 to ground, and apply 12 volts to relay pin No. 86. See Fig 1 . Check for continuity between relay pins No. 30 and 87. If continuity exists, verify results of step 5). If continuity does not exist, replace main power relay.
  12. Turn ignition off. Remove main power relay. Check for continuity between main power relay wiring harness connector pin No. 87A and ground. See Fig 1 . If continuity exists, go to next step. If continuity does not exist, repair circuit No. 651 (Black/Yellow wire).
  13. Install main power relay. Connect jumper wire between test pins No. 19 and 34 on breakout box. Turn ignition on. Measure voltage between breakout box test pins No. 52 and 60. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair circuit No. 797 (Light Green/Purple wire), No. 603 (Dark Green wire) or fuse.
  14. Turn ignition off. Measure resistance between breakout box test pins No. 8 and 26. If resistance is more than 5 ohms, go to next step. If resistance is less than 5 ohms, go to step 16).
  15. Disconnect fluid level indicator 2-pin connector from Hydraulic Control Unit (HCU) reservoir. See COMPONENT LOCATIONS  . Measure resistance between reservoir sensor pins. If resistance is less than 5 ohms, repair circuit No. 493 (Black/Pink wire). If resistance is more than 5 ohms, replace HCU reservoir.
  16. Disconnect ABS control module 55-pin connector. Check connector for loose pins and corrosion. Clean or repair connector as necessary. Reconnect connector. Turn ignition on.
  17. Perform ABS QUICK CHECK CHART. See Figure . If no faults are indicated, replace ABS control module with a known-good unit. If ABS warning light goes off, replace ABS control module. If ABS warning light stays on, verify all tests have been performed correctly. Repeat tests as necessary.
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