Headlamps Stay On When Headlamp Switch Is In Auto Mode - keywords battery dead drain

PIC3483C Was created to remove the information that a fix was being worked on. No updated calibration will be available. If the vehicle were to ever lose power at night while still rolling, the current would allow the headlamps to stay on. Please discard PIC3483B

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

With headlamp switch in "Auto" mode, headlamps may remain on with ignition switched off and driver's door opened. Headlamps will remain on, potentially discharging the vehicle battery.

The BCM does not recognize that speed has dropped below 6 Mph if ignition is turned off prior to or as the vehicle comes to a stop. Due to a lag in updating vehicle speed, depending on the rate at which the vehicle is stopped, the BCM may continue to register some vehicle speed momentarily after the vehicle has actually come to a stop. To activate the headlamp off condition, BCM must register a vehicle speed of zero, as well as driver's door switch cycled. If the ignition is switched off while the BCM is registering 6 Mph or greater, the headlamps will remain on even following cycling of the drivers door switch.

As the vehicle condition cannot be rectified, customers experiencing this condition must be advised to ensure that the vehicle is brought to a complete stop, and perhaps delay switching off the ignition momentarily after stopping the vehicle.

No other action should be attempted in order to overcome this condition.

Note For The 2004 GTO Only:: If the BCM does not receive the door open input from the driver door jamb switch, due to corrosion or a poor connection, the BCM will not turn off the headlamps. The BCM uses the jamb switch to see the door open as opposed to using the switch in the latch. You can see the latch switch on the BCM data stream, but not the jamb switch.

Remove the door jamb switch to inspect for corrosion or a poor connection at the switch. The door jamb switch is held in place by a screw and is easily removed for inspection. On the 2004 GTO, the door jamb switch is located just below the A-pillar. If corrosion is found, replace the door jamb switch and verify proper operation of the auto headlamps.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.