2006 Grand Caravan Headlight problems
Posted December 28, 2010 at 11:38 am
My kid sister called me last night, she is having a weird problem with the headlights on her 2006 Grand Caravan. Her daytime running lights are working fine but when it got dark and she turned on her headlights she noticed that she has no normal headlights and she only has high-beams when the control arm is held toward the driver. As soon as you let go of he arm, it should toggle high beams on/off but when the arm is let go, it goes back to only drl. I honestly don't know where to suggest she start - fuses, lights or the multi-function switch in the column. She has to drive back to Alberta through the mountains from BC in a few days. Any suggestions would be appreciated. I am new to allpar so if I have posted in the wrong area just let me know where I should have posted.
Posted December 28, 2010 at 02:13 pm
Really everything 'headlight' is module-controlled. The multifunction switch sends a signal of what is being selected to the BCM (body control module) and the BCM sends a signal over the PCI bus to the FCM (front control module) which controls the headlamp operation. There may be fault codes stored in either module to assist in diagnosis and a good scan tool can show what the modules are or aren't seeing with the headlamp switch turned on. .
The configuration of the headlamp system of headlamps, park lamps and fog lamps is determined by the BCM. The BCM determines the lighting configuration as a result of the inputs from the ignition switch, headlamp switch and multi-function switch. A PCI bus is transmitted from the BCM to the FCM to enable the necessary drivers to set the illumination configuration. Four wires are connected between the headlamp switch and the BCM. The first wire contains information regarding the position of the headlamp switch (Off, Automatic Headlamps, Automatic Headlamp switch fog, Park with Fog, Head, or Head with Fog Lamps). The second wire contains information regarding the position of the dimmer switch (Dome Lamp, Daytime Brightness, Dimming Level or Off). The third wire is a dedicated signal return (ground) wire. The fourth wire provides power to the front fog lamp indicator.