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Test G: Audio Control Module (ACM) Does Not Respond To NGS Tester

  1. Turn ignition switch to LOCK position. Disconnect ACM harness connector C240a. Inspect harness connector for loose, damaged or corroded terminals. If problem exists, repair harness connector as necessary and retest system for normal operation. If problem does not exist, go to next step.
  2. Connect ACM harness connector C240a and connect NGS tester. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester indicates ACM: NO RESPONSE ON CKT 914 (BUS +), go to next step. If NGS tester indicates ACM: NO RESPONSE ON CKT 915 (BUS -), go to step  6 .
  3. Turn ignition switch to LOCK position. Disconnect NGS tester. Disconnect ACM harness connector C240a. Measure resistance between terminal No. 3 (Gray/Black wire) at ACM harness connector C240a and terminal No. 2 (Gray/Red wire) at Data Link Connector (DLC). See Figure and Fig 1 . If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, replace ACM and retest system for normal operation.
  4. Disconnect joint connector No. 4 harness connector C223, located behind left side of instrument panel. Measure resistance in Gray/Black wire between terminal No. 16 at joint connector No. 4 harness connector C223 and terminal No. 3 at ACM harness connector C240a. See Figure and Fig 1 . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Gray/Black wire between joint connector No. 4 and ACM. Retest system for normal operation.
  5. Measure resistance between terminals No. 14 and 16 at joint connector No. 4 (component side). See Figure . If resistance is 5 ohms or less, repair open in Gray/Red wire between joint connector No. 4 and DLC. Retest system for normal operation. If resistance is greater than 5 ohms, replace joint connector No. 4 and retest system for normal operation.
  6. Turn ignition switch to LOCK position. Disconnect NGS tester. Disconnect ACM harness connector C240a. Measure resistance between terminal No. 4 (Blue/Yellow wire) at ACM harness connector C240a and terminal No. 10 (Blue/Red wire) at Data Link Connector (DLC). See Figure and Fig 1 . If resistance is 5 ohms or less, replace ACM and retest system for normal operation. If resistance is greater than 5 ohms, go to next step.
  7. Disconnect joint connector No. 4 harness connector C223, located behind left side of instrument panel. Measure resistance in Blue/Yellow wire between terminal No. 7 at joint connector No. 4 harness connector C223 and terminal No. 4 at ACM harness connector C240a. See Figure and Fig 1 . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Blue/Yellow wire between joint connector No. 4 and ACM. Retest system for normal operation.
  8. Measure resistance between terminals No. 7 and 9 at joint connector No. 4 (component side). See Figure . If resistance is 5 ohms or less, repair open in Blue/Red wire between joint connector No. 4 and DLC. Retest system for normal operation. If resistance is greater than 5 ohms, replace joint connector No. 4 and retest system for normal operation.
Fig 1: Identifying Audio Control Module Harness Connector Terminals
G00011083Courtesy of FORD MOTOR CO.
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