DTC B2577: Head Lamp Control Circuit Low: Testing
WARNING: This page is about a different car, the 1999 Pontiac Grand Am and 1999 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If circuit is shorted to ground, fuse will blow. Check fuse before performing diagnostics.
- Perform BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS. Go to next step.
- Replace ALC relay with a known-good relay. Using scan tool, activate ALC relay. If ALC relay activates, go to step 10 . If ALC relay does not activate, go to next step.
- With original ALC relay in underhood junction block, use DVOM to backprobe for voltage between underhood junction block connector C3 terminal A9 (Pink/White wire) and ground. See WIRING DIAGRAMS . If battery voltage is indicated, go to step 5 . If battery voltage is not indicated, go to next step.
- Replace underhood junction block. After repairs, go to step 10 .
- Disconnect BCM connector C1. Using DVOM, measure resistance between BCM connector C1 terminal A1 (Pink/White wire) and ground. See Figure . If no resistance is indicated (infinite), go to step 7 . If any resistance is indicated, go to next step.
- Repair short to ground in Pink/White wire between BCM and underhood junction block. After repairs, go to step 10 .
- Using DVOM, measure resistance between BCM connector C1 terminal A1 and underhood junction block (Pink/White wire). If reading is less than 2 ohms, go to step 9 . If reading is greater than 2 ohms, go to next step.
- Repair open in Pink/White wire between BCM and underhood junction block. After repairs, go to step 10 .
- Replace BCM. See BODY CONTROL MODULE under REMOVAL & INSTALLATION. After repairs, go to next step.
- Using scan tool, clear DTCs. Go to BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS.