Headlight Switch Input Failure
NOTE:
After making any repairs, perform BODY CONTROL MODULES SYSTEM VERIFICATION TEST
under VERIFICATION TESTS.
- Turn ignition off. Ensure headlight switch is off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, read HEADLIGHT SWITCH voltage. If voltage is more than 4.8 volts, go to next step. If voltage is 4.8 volts or less, go to step 7 .
- Turn ignition off. Disconnect headlight switch connector. Turn ignition on. Measure voltage between ground and headlight switch connector terminal No. 12, headlight switch MUX circuit (Yellow wire). See Fig 1 . If voltage is more than 5.3 volts, leave headlight switch connector disconnected, and go to next step. If voltage is 5.3 volts or less, leave headlight switch connector disconnected, and go to step 5 .
- Turn ignition off. Disconnect Body Control Module (BCM) connector C2. Measure resistance of headlight switch return circuit (White wire) between BCM connector C2 terminal No. 19 and headlight switch connector terminal No. 6. See Figure and Fig 1 . If resistance is less than 5 ohms, leave connectors disconnected, and go to next step. If resistance is 5 ohms or more, repair open in White wire.
- Turn ignition on. Measure voltage between ground and BCM connector terminal No. 2, headlight switch MUX circuit (Yellow wire). If any voltage exists, repair short to voltage in Yellow wire. If no voltage exists, replace BCM.
- Turn ignition off. Disconnect Body Control Module (BCM) connector C2. Measure resistance of headlight switch MUX circuit (Yellow wire) between BCM connector C2 terminal No. 2 and headlight switch connector terminal No. 12 C2. See Figure and Fig 1 . If resistance is less than 5 ohms, leave headlight switch connector disconnected, and go to next step. If resistance is 5 ohms or more, repair open in Yellow wire.
- Connect BCM connector C2. Connect a fused jumper wire between headlight switch connector terminal No. 6, headlight switch return circuit (White wire) and No. 12, headlight switch MUX circuit (Yellow wire). Using scan tool, read HEADLIGHT SWITCH voltage. If voltage is zero volts, replace headlight switch. If voltage is more than zero volts, leave headlight switch connector disconnected, and go to next step.
- Disconnect jumper wire. Using scan tool, read HEADLIGHT SWITCH voltage. If voltage is 4.8-5.2 volts, replace headlight switch. If voltage is not 4.8-52 volts, leave headlight switch connector disconnected, and go to next step.
- Turn ignition off. Disconnect BCM connector C2. Measure resistance between ground and BCM connector C2 terminal No. 12, headlight switch MUX circuit (Yellow wire). See Figure . If resistance is less than 100 ohms, repair short to ground in Yellow wire. If resistance is 100 ohms or more, replace BCM.