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DTC B1508: High Power Control Circuit High: Testing

  1. Remove rear window defogger relay from right I/P accessory wiring junction block. Turn ignition switch to RUN position. Connect a test light between ground and rear window defogger relay control circuit terminal N3. See WIRING DIAGRAMS  . Using scan tool, command rear window defogger relay ON and OFF. If test light turns on and off as commanded, go to DIAGNOSTIC AIDS  . If test light does not turn on and off as commanded, go to next step.
  2. Check for short to power in power sun roof and heated seat (if equipped) control circuit (Orange wire) between right I/P accessory wiring junction block harness connector C1 terminal D11 and BCM harness connector C2 terminal B8. See Figure and Figure . Repair as necessary. See WIRING DIAGRAMS  . After repair, go to step  5 .
  3. Check for poor terminal contact at BCM harness connector C2. Repair as necessary. After repair, go to step  5 . If terminal contact is okay, go to next step.
  4. Replace BCM. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION. Perform new BCM setup. See NEW BCM SETUP  under PROGRAMMING. After programming BCM, go to next step.
  5. Using scan tool, clear DTCs. Operate vehicle within conditions that caused DTC. If DTC B1508 resets, go to step  1 . If DTC B1508 does not exist, system is okay at this time.
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