Fog/Driving Lamp: Description and Operation

System Description
Control of the fog lamps is dependent upon the position of the combination switch (lighting switch). When the lighting switch is placed in the fog lamp position the BCM receives input requesting the fog lamps to illuminate. When the head lamps are illuminated, this input is communicated to the IPDM E/R (intelligent power distribution module engine room) across the CAN communication lines. The central processing unit of the IPDM E/R controls the front fog lamp relay coil. When activated, this relay directs power to the front fog lamps.

OUTLINE
Power is supplied at all times
- through 15 A fuse [No. 41 located in the IPDM E/R (intelligent power distribution module engine/room)]
- to front fog lamp relay, located in the IPDM E/R, and Power is also supplied at all times
- to terminal 7 of the BCM (body control module).

When the ignition switch is in ON or START position, power is supplied
- to terminal 35 of the BCM.

When the ignition switch is in ACC or ON position, power is supplied
- to terminal 36 of the BCM.

Ground is supplied
- to BCM terminals 8, 27, and 63
- through body grounds M57, M61, E15, and E24.

FOG LAMP OPERATION
The fog lamp switch is built into the combination switch. The lighting switch must be in the 2ND position and low (B) position, and the fog lamp switch must be ON for fog lamp operation.

With the fog lamp switch in the ON position, the central processing unit of the IPDM E/R (intelligent power distribution module engine room) grounds the coil side of the fog lamp relay. The fog lamp relay then directs power
- to front fog lamp LH terminal 1
- through IPDM E/R terminal 32, and
- to front fog lamp RH terminal 1
- through IPDM E/R terminal 29.

Ground is supplied
- to front fog lamp LH terminal 2
- through body grounds E15 and E24, and
- to front fog lamp RH terminal 2
- through body grounds E115 and E129.

With power and grounds supplied, the front fog lamps illuminate.

BATTERY SAVER CONTROL
When the combination switch (lighting switch) is in the 1ST or 2ND position (ON), the fog lamp switch is ON, and the ignition switch is turned from ON or ACC to OFF, the battery saver control feature is activated.

Under this condition, the fog lamps (and headlamps) remain illuminated for 5 minutes, unless the combination switch (lighting switch) position is changed. If the combination switch (lighting switch) position is changed, then the fog lamps (and headlamps) are turned off.

CAN Communication System Description
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.