Wiper and Washer Systems: Description and Operation

FRONT WIPER AND WASHER SYSTEM

System Description
- All front wiper relays (HI, LO) are included in IPDM E/R.
- Wiper switch (combination switch) is composed of a combination of 5 output terminals and 5 input terminals. Terminal combination status is read by BCM when switch is turned ON.
- BCM controls front wiper LO, HI, and INT (intermittent) operation.
- IPDM E/R operates wiper motor according to CAN communication signals from BCM.

LOW SPEED WIPER OPERATION
Power is supplied at all times
- from BCM (input 1) terminal 48
- to combination switch terminal 1
- to 20 A fuse (No. 39, located in the IPDM E/R) and
- through IPDM E/R terminal 42
- to wiper motor terminal B.

When the ignition switch is in the ON or START position, and front wiper switch is turned to LO position, front wiper LO contact in combination switch comes ON, and Power is supplied
- through combination switch terminal 3
- to BCM (output 3) terminal 50.

When BCM determines that wiper switch is in LO position, it uses CAN communications and Front wiper request signal (LO) is sent
- from BCM terminals 70 and 71
- to IPDM E/R terminals 48 and 49.

When IPDM E/R receives front wiper request signal (LO), it turns ON front wiper relay (in IPDM E/R).
Ground is supplied
- from wiper motor terminal L,
- through IPDM E/R terminal 31 and front wiper relay
- to IPDM E/R terminal 16
- through body grounds E15 and E24.

With power and ground supplied, the front wiper motor operates at low speed.

HI SPEED WIPER OPERATION
Power is supplied at all times
- from BCM (input 2) terminal 49
- to combination switch terminal 2
- to 20 A fuse (No. 39, located in the IPDM E/R) and
- through IPDM E/R terminal 42
- to wiper motor terminal B.

When the ignition switch is the ON or START position, and the front wiper switch is turned to HI position, front wiper HI contact in combination switch comes ON, and Power is supplied
- through combination switch terminal 10
- to BCM (output 3) terminal 41.

When BCM determines that wiper switch is in HI position, it uses CAN communications and Front wiper request signal (HI) is sent to IPDM E/R
- from BCM terminals 70 and 71
- to IPDM E/R terminals 48 and 49.

When the IPDM E/R receives front wiper request signal (HI), it energizes the front wiper relay and front wiper HI relay. Under this condition, Ground is supplied.
- to front wiper motor terminal H
- through IPDM E/R terminal 30 and front wiper relay and front wiper HI relay
- to IPDM E/R terminal 16
- through body grounds E15 and E24.

With power and ground supplied, the front wiper motor operates at high speed.

INTERMITTENT OPERATION
Power is supplied at all times
- from BCM (input 2) terminal 49
- to combination switch terminal 2.

When the ignition switch is in ON or START position, and the front wiper switch is turned to INT position, the front wiper INT contact in the combination switch comes ON, and power is supplied
- from combination switch terminal 1.
- to BCM (output 1) terminal 47.

When BCM determines that combination switch status is front wiper INT ON, it performs the following operations.
- When BCM detects ON/OFF status of intermittent operation dial positions 1, 2, and 3 (in same way as wiper INT), it determines wiper dial position status.
- BCM calculates operation interval from wiper dial position and vehicle speed signal received from combination meter through CAN communications.
- BCM sends front wiper request signal (INT) to IPDM E/R at calculated operation interval.

When IPDM E/R receives front wiper request signal (INT), it turns ON internal front wiper relay. It then sends auto-stop signal to BCM, and conducts intermittent front wiper motor operation.

AUTO STOP OPERATION
With wiper switch turned OFF, wiper motor will continue to operate until wiper arms reach windshield base.

When wiper arms are not located at base of windshield with wiper switch OFF, ground is provided
- from terminal 31 of the IPDM E/R
- to front wiper motor terminal L, in order to continue wiper motor operation at low speed.

Ground is also supplied
- through terminal 38 of the IPDM E/R
- to front wiper motor terminal P
- through terminal E of the front wiper motor and
- through body grounds E15 and E24.

When wiper arms reach base of windshield, front wiper motor terminals P and B are connected instead of terminals P and E.
Then the IPDM E/R sends auto stop operation signal to BCM with CAN communication line.
When BCM receives auto stop operation signal, BCM sends wiper stop signal to IPDM E/R with CAN communication line.
IPDM E/R stops wiper motor. Wiper motor will then stop wiper arms at the STOP position.

WASHER OPERATION
When the ignition switch is in ON or START position, power is supplied
- through 10 A fuse (No. 46 located in the IPDM E/R)
- through IPDM E/R terminal 18
- to washer motor terminal +.

When front wiper switch is turned to washer position,
Ground is supplied
- to washer motor terminal -
- through combination switch terminal 11
- through combination switch terminal 12
- from body grounds M57 and M61.

With ground supplied, the front washer motor is operated, and at the same time,
Power is supplied
- through combination switch terminal 7
- to BCM (output 2) terminal 40.

When BCM detects that front washer motor has operated for 0.4 seconds or longer, BCM uses CAN communication and sends wiper request signal to IPDM E/R for low speed operation of wipers.

When BCM detects that washer switch is OFF, low speed operation cycles approximately 3 times and then stops.

MIST OPERATION
When the wiper switch is turned to the mist position, wiper low speed operation cycles once and then stops. For additional information about wiper operation under this condition, refer to "LOW SPEED WIPER OPERATION".
If the switch is held in the mist position, low speed operation continues.

FAIL-SAFE FUNCTION
BCM includes fail-safe function to prevent malfunction of electrical components controlled by CAN communications if a malfunction in CAN communications occurs.

BCM uses CAN communications to stop output of electrical components it controls.

Until ignition switch is turned off, front wiper remains in same status as just before fail-safe control was initiated.
(If wiper was in low speed operation just before fail-safe, it continues low speed operation until ignition switch is turned OFF.)

When fail-safe status is initiated, BCM remains in standby until normal signals are received. When normal signals are received, fail-safe status is canceled.

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.