Exterior Lighting Test 2A - Auto Headlights Inoperative
NOTE:
Perform EXTERIOR LIGHTING TEST 1A
before proceeding with this test. For connector terminal identification, refer to CONNECTOR IDENTIFICATION
. For wiring diagrams, refer to WIRING DIAGRAMS
. After each repair, perform TEST VER-1A
.
CAUTION:
Always turn ignition switch to OFF position prior to disconnecting any module connector. Ensure all connectors are clean and tight.
- Using scan tool, select BODY COMPUTER SYSTEM TEST, then PCM MONITOR. If scan tool does not displays PCM ACTIVE ON THE BUS, go to VEHICLE COMMUNICATIONS TEST 10A . If scan tool displays PCM ACTIVE ON THE BUS, go to next step.
- Using scan tool, actuate headlight relay. If headlights do not illuminate, go to EXTERIOR LIGHTING TEST 2B . If headlights illuminate, turn headlight switch to AUTO. If scan tool displays ENABLED, go to next step. If scan tool does not display ENABLED, go to EXTERIOR LIGHTING TEST 2C .
- Disconnect auto headlight sensor. Auto headlight sensor is located on center of defroster grille, at base of windshield. Ensure headlight switch is in AUTO position. Start engine. If headlights illuminate, replace auto headlight sensor. If headlights do not illuminate, go to next step.
- Turn engine off. Disconnect Body Control Module (BCM) White 24-pin connector. BCM is located under left side of dash. BCM is mounted to junction block located behind left end cap of instrument panel. See Figure in CHIME TEST 2A. Using scan tool in ohmmeter mode, measure resistance at terminal No. 4 (Orange/Black wire) on auto headlight sensor connector. If resistance is less than 500 ohms, repair short to ground in Orange/Black wire. If resistance is 500 ohms or more, replace BCM.