Test B: Audio Control Module (ACM) Does Not Respond To NGS Tester
NOTE:
Audio Control Module (ACM) may also be referred to as Front Control Unit (FCU).
- Turn ignition switch to LOCK position. Disconnect ACM 16-pin harness connector C224 located behind center of instrument panel, on radio. Inspect harness connector for loose, damaged or corroded terminals. Repair as necessary and retest system for normal operation. If harness connector is okay, reconnect harness connector. Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM. If NGS tester indicates FCU: NO RESPONSE ON CKT 914 (BUS +), go to next step. If NGS tester indicates FCU: NO RESPONSE ON CKT 915 (BUS -), go to step 3 .
- Turn ignition switch to LOCK position. Disconnect New Generation Star (NGS) tester. Measure resistance in Tan/Orange wire between terminal No. 3 at ACM harness connector C224 and terminal No. 2 at Data Link Connector (DLC). See Fig 1 . If resistance is 5 ohms or less, replace ACM. If resistance is greater than 5 ohms, repair open in Tan/Orange wire between ACM and DLC.
- Turn ignition switch to LOCK position. Disconnect New Generation Star (NGS) tester. Measure resistance in Pink/Light Blue wire between terminal No. 4 at ACM harness connector C224 and terminal No. 10 at DLC. If resistance is 5 ohms or less, replace ACM. If resistance is greater than 5 ohms, repair open in Pink/Light Blue wire between ACM and DLC.