Turn Signals: Description and Operation

System Description

TURN SIGNAL OPERATION
When the ignition switch is in the ON or START position, power is supplied
- through 10 A fuse [No. 12, located in the fuse block (J/B)]
- to BCM (body control module) terminal 35, and
- through 10 A fuse [No. 14, located in the fuse block (J/B)]
- to terminals 17 and 18 of the combination meter.

Ground is supplied
- to BCM (body control module) terminals 8, 27, and 63
- through body grounds M57, E15, and E24, and
- to combination meter terminals 6 and 39
- through body grounds M57 and M61.

LH Turn
When the turn signal switch (combination switch) is moved to the L position, the BCM (body control module) receives input requesting the left turn signals to flash. The BCM then supplies power
- to front turn signal lamp LH terminal 3
- to rear turn signal lamp LH (part of the rear combination lamp LH) terminal 3.

Ground is supplied to the front turn signal lamp LH terminal 2 through body grounds E15 and E24. Ground is supplied to the rear turn signal lamp LH (part of the rear combination lamp) terminal 5 through body grounds B7 and B19.

The BCM also supplies ground to combination meter terminals 1 and 2 across the CAN communication lines. This input is processed by the central processing unit of the combination meter, which in turn supplies ground to the left turn signal indicator lamp.

With power and ground supplied, the BCM controls the flashing of the LH turn signal lamps.

RH Turn
When the turn signal switch (combination switch) is moved to the R position, the BCM (body control module) receives input requesting the right turn signals to flash. The BCM then supplies power
- to front turn signal lamp RH terminal 3
- to rear turn signal lamp RH (part of the rear combination lamp RH) terminal 3.

Ground is supplied to the front turn signal lamp RH terminal 2 through body grounds E115 and E129.

Ground is supplied to the rear turn signal lamp RH (part of the rear combination lamp RH) terminal 5 through body grounds B7 and B19.

The BCM also supplies ground to combination meter terminals 1 and 2 across the CAN communication lines. This input is processed by the central processing unit of the combination meter, which in turn supplies ground to the right turn signal indicator lamp.

With power and ground supplied, the BCM controls the flashing of the RH turn signal lamps.

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.