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DTC B2603: DRL Control #1 Circuit High: Testing

  1. Perform lighting system diagnostic system check. See LIGHTING SYSTEM DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. Turn ignition off. Connect scan tool to DLC. Turn ignition on, with engine off. Use scan tool to command left front turn signal ON and OFF. If left front turn signal turns ON and OFF with each command, go to DIAGNOSTIC AIDS  . If left front turn signal does not turn ON and OFF with each command, go to next step.
  3. Turn ignition off. Disconnect left front turn signal. Turn ignition on, with engine off. Using a test light connected to ground, probe Orange wire at left front turn signal. See appropriate EXTERIOR LIGHTS wiring diagram. If test light illuminates, go to next step. If test light does not illuminate, go to step  10 .
  4. Connect test light between Light Blue and Black wires of left front turn signal. Using scan tool, command left front turn signal ON and OFF. If test light illuminates each time turn signal is turned ON and OFF, go to step  8 . If test light does not illuminate each time turn signal is turned ON and OFF, go to next step.
  5. If test light stays illuminated each time turn signal is turned ON and OFF in above step, go to step  7 . If test light does not stay illuminated each time relay is turned ON and OFF in above step, go to next step.
  6. Test Light Blue wire between left front turn signal and BCM harness connector C1 terminal "E" for short to voltage or an open. See WIRING DIAGRAMS  . After repair, go to step  13 . If fault is not located and condition still exists, go to step  9 .
  7. Test Light Blue wire between left front turn signal and BCM harness connector C1 terminal E for short to ground. See WIRING DIAGRAMS  . After repair, go to step  13 . If fault is not located and condition still exists, go to step  9 .
  8. Inspect for poor connections at left front turn signal. After repair, go to step  13 . If fault is not located and condition still exists, go to step  11 .
  9. Inspect for poor connections at BCM connector C1. After repair, go to step  13 . If fault is not located and condition still exists, go to step  12 .
  10. Repair Orange wire between left front turn signal and underhood accessory wiring junction block. See appropriate EXTERIOR LIGHTS wiring diagram. After repair, go to step  13 .
  11. Replace left front turn signal. After repair, go to step  13 .
  12. Replace BCM. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION. After replacement, perform set up procedure. See NEW BCM SETUP  under PROGRAMMING. After replacement, go to next step.
  13. Using scan tool, clear BCM DTCs. Operate vehicle within conditions to set DTC. If DTC B2603 resets, return to step  2 . If DTC B2603 does not reset, system is okay.
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