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Lighting System Diagnostic Check

WARNING: This page is about a different car, the 2001 Cadillac Seville. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool to Data Link Connector (DLC). DLC is located below left side of instrument panel, near steering column. See Figure . If scan tool powers up, go to next step. If scan tool does not power up, perform TEST A: SCAN TOOL DOES NOT POWER UP  under SYSTEM TESTS.
  2. Turn ignition switch to RUN position. Using scan tool, attempt to establish communication with Dash Integration Module (DIM), Instrument Panel Module (IPM), Rear Integration Module (RIM) and Instrument Panel Cluster (IPC). If scan tool communicates with DIM, IPM, RIM and IPC, go to next step. If scan tool does not communicate with DIM, IPM, RIM and IPC, perform TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE  under SYSTEM TESTS.
    3. CAUTION: Engine may start during the following step. Turn ignition switch to OFF position as soon as you have observed crank power mode.
  3. Using scan tool, access class 2 power mode. Cycle ignition switch through all positions, while observing ignition switch power mode parameter. If ignition switch parameter matches ignition switch positions, go to next step. If ignition switch parameter does not match ignition switch positions, perform TEST C: POWER MODE MISMATCH  under SYSTEM TESTS.
  4. Using scan tool, select DISPLAY DTCs function for DIM, IPM RIM and IPC. If scan tool displays any DTC, go to next step. If scan tool does not display any DTCs, repair lighting system by symptom. See appropriate EXTERIOR LIGHTS article.
  5. If scan tool does not display any DTCs which begin with "U", go to next step. If scan tool displays any DTCs which begin with "U", perform TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE  under SYSTEM TESTS.
  6. If scan tool does not display DTCs B1000, B1004, B1007, or B1009, go to next step. If scan tool displays DTCs B1000, B1004, B1007, or B1009, perform appropriate test in accordance with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
  7. If scan tool displays DTCs B1327 or B1328, perform appropriate test in accordance with DTC retrieved. See GENERATORS & REGULATORS - SEVILLE article in STARTING & CHARGING SYSTEMS. If scan tool does not display DTCs B1327 or B1328, perform appropriate test in accordance with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
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