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DTC B2587: ALC Parking Light Relay Output Short To Ground/Open: Testing

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in BFC DIAGNOSTIC SYSTEM CHECK  .
  2. Remove ALC parking light relay from underhood wiring harness junction block. Replace ALC parking light relay with a known-good relay. Using scan tool, enable ALC parking light relay. If ALC parking light relay operates properly, go to step 10). If ALC parking light relay does not operate properly, go to next step.
  3. Ensure ALC parking light relay is installed in underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B8 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B1 (White wire). Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and underhood wiring harness junction block connector C3, terminal B8 (White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See REMOVAL & INSTALLATION  . Go to next step.
  10. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .


  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in BFC DIAGNOSTIC SYSTEM CHECK  .
  2. Remove ALC parking light relay from underhood wiring harness junction block. Replace ALC parking light relay with a known-good relay. Using scan tool, enable ALC parking light relay. If ALC parking light relay operates properly, go to step 10). If ALC parking light relay does not operate properly, go to next step.
  3. Ensure ALC parking light relay is installed in underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B8 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B1 (White wire). Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and underhood wiring harness junction block connector C3, terminal B8 (White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See REMOVAL & INSTALLATION  . Go to next step.
  10. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .
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