Headlights Will Not Turn Off
NOTE:
For connector terminal identification and wiring diagrams, see
BODY CONTROL COMPUTER - INTRODUCTION article. Perform VERIFICATION TEST VER-1A
after each repair.
CAUTION:
Always turn ignition switch to OFF position prior to disconnecting or connecting any module connector.
- Using scan tool, select BODY CONTROL MODULE. If scan tool displays NO RESPONSE or CCD BUS FAILURE, go to appropriate VEHICLE COMMUNICATIONS article. If scan tool does not display NO RESPONSE or CCD BUS FAILURE, go to next step.
- Using scan tool, read headlight switch sense. If scan tool displays HEADLAMP SW: CLOSED, go to next step. If scan tool does not display HEADLAMP SW: CLOSED, go to step 5 .
- Disconnect headlight switch. Read headlight switch sense. If scan tool displays HEADLAMP SW: CLOSED, go to next step. If scan tool does not display HEADLAMP SW: CLOSED, replace headlight switch.
- Disconnect Body Control Module (BCM) connector "A". BCM is located with junction block under driver's side instrument panel junction block connector "A". See Figure . Using scan tool in ohmmeter mode, measure resistance on headlight switch 8-pin connector terminal No. 3 (Light Green/Orange wire). If resistance is less than 5 ohms, repair Light Green/Orange wire for short to ground. If resistance is 5 ohms or more, replace Body Control Module (BCM).
- Disconnect low beam headlight relay. Low beam headlight relay is located in Power Distribution Center located under hood next to battery. See Fig 1 . If headlights turn off, go to next step. If headlights do not turn off, replace Power Distribution Center (PDC).
- If vehicle is equipped with quad headlight system, go to next step. If vehicle is not equipped with quad headlight system, go to step 9 .
- Disconnect Body Control Module (BCM) connector "B". BCM is located with junction block under driver's side instrument panel. See Figure . Using external ohmmeter, measure resistance between ground and BCM connector "B" terminal No. 76 (Orange/White wire). If resistance is less than 100 ohms, repair Orange/White wire for short to ground. If resistance is 100 ohms or more, go to next step.
- Measure resistance between ground and low beam relay connector terminal No. 85 (Orange/White wire). If resistance is less than 100 ohms, replace BCM. If resistance is 100 ohms or more, replace low beam relay.
- Disconnect multifunction switch connector. Using scan tool in ohmmeter mode, measure resistance on multifunction switch connector terminal No. 9 (Pink wire). If resistance is less than 5 ohms, repair Pink wire for short to ground between multifunction switch and junction block. If resistance is 5 ohms or more, go to next step.
- Disconnect low beam headlight relay. Measure resistance on low beam relay connector terminal No. 85 (Orange/White wire). If resistance is less than 5 ohms, repair Orange/White wire for short to ground. If resistance is 5 ohms or more, replace low beam headlight relay.