System Description: Notes

WARNING: This page is about a different car, the 2009 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

Headlamp operation is controlled by the BCM (body control module) based on inputs from the combination switch (lighting switch). When the lighting switch is placed in the 2ND position, the BCM receives an input signal requesting the headlamps (and tail lamps) illuminate. The request is then communicated to the IPDM E/R (intelligent power distribution module engine room) via the CAN communication lines. The CPU (central processing unit) located in the IPDM E/R controls ground for the headlamp high and headlamp low relay coils. These relays direct power to the respective headlamps, which then illuminate. When the headlamp switch is OFF or in the 1ST position (parking lamps ON), the parking brake is released and the engine is running, the IPDM E/R de-energizes the headlamp relays and supplies ground to the daytime light relay 1 to actuate the daytime light function.