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DTC B2602: DRL Relay Output Short To Ground/Open: Testing

WARNING: This page is about a different car, the 1998 Oldsmobile Cutlass and 1998 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
  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 DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool,enable DRL relay. If automatic lighting control operates properly, go to step 10). If automatic light control does not operate properly, go to next step.
  3. Reinstall DRL relay. Back out underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal B12 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black 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 B5 (Light Green/Black wire). Using DVOM, check resistance between BFC harness connector C1, terminal B5 (Light Green/Black 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 Light Green/Black 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 B5 (Light Green/Black wire) and underhood wiring harness junction block harness connector C3, terminal B12 (Light Green/Black 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 Light Green/Black 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 DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool,enable DRL relay. If automatic lighting control operates properly, go to step 10). If automatic light control does not operate properly, go to next step.
  3. Reinstall DRL relay. Back out underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal B12 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black 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 B5 (Light Green/Black wire). Using DVOM, check resistance between BFC harness connector C1, terminal B5 (Light Green/Black 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 Light Green/Black 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 B5 (Light Green/Black wire) and underhood wiring harness junction block harness connector C3, terminal B12 (Light Green/Black 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 Light Green/Black 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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