Wiper and Washer Systems: Description and Operation
FRONT WIPER AND WASHER SYSTEMSystem Description
- Both front wiper relays are located in the IPDM E/R (intelligent power distribution module engine room).
- Wiper switch (combination switch) is composed of a combination of 5 output terminals and 5 input terminals. Terminal combination status is read by BCM (body control module) 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 the BCM.
Power is supplied at all times
- through 50 A fusible link (letter f, located in the fuse and fusible link box)
- to BCM terminal 55, and
- through 20 A fuse (No. 39, located in the IPDM E/R)
- to front wiper relay (located in the IPDM E/R).
With the ignition switch in ON or START position, power is supplied
- through 10 A fuse [No. 1, located in the fuse block (J/B)]
- to BCM terminal 38, and
- through 10 A fuse (No. 47, located in the IPDM E/R)
- through IPDM E/R terminal 44
- to front washer motor terminal +.
Ground is supplied
- to BCM terminal 52
- to combination switch terminal 12
- through grounds M57, M61 and M79, and
- to IPDM E/R terminals 38 and 60
- to front wiper motor terminal E
- through grounds E15 and E24.
LOW SPEED WIPER OPERATION
When the ignition switch is in the ON or START position, and the front wiper switch is turned to low position, the BCM detects a low speed wiper ON signal by BCM wiper switch reading function.
BCM then sends front wiper (low) request signal over CAN communication, lines
- from BCM terminals 39 and 40
- to IPDM E/R terminals 48 and 49.
When IPDM E/R receives front wiper (low) request signal, it supplies ground to energize the front wiper relay.
With the front wiper relay energized, power is supplied
- through front wiper relay
- to front wiper HI relay
- through IPDM E/R terminal 21
- to front wiper motor terminal L.
With power and ground supplied, the front wiper motor operates at low speed.
HI SPEED WIPER OPERATION
When the ignition switch is in the ON or START position, and the front wiper switch is turned to high position, the BCM detects a high speed wiper ON signal by BCM wiper switch reading function.
BCM then sends front wiper (high) request signal over CAN communication lines
- from BCM terminals 39 and 40
- to IPDM E/R terminals 48 and 49
When IPDM E/R receives front wiper (high) request signal, it supplies ground to energize the front wiper and the front wiper HI relays.
With the front wiper and the front wiper HI relays energized, power is supplied
- through front wiper relay
- to front wiper HI relay
- through IPDM E/R terminal 31
- to front wiper motor terminal H.
With power and ground supplied, the front wiper motor operates at high speed.
INTERMITTENT OPERATION
Wiper intermittent operation delay interval is determined from the combination of the intermittent wiper dial position inputs and vehicle speed. During each intermittent operation delay interval, the BCM sends a front wiper request signal to the IPDM E/R to operate the wipers.
When the ignition switch is in ON or START position, and the front wiper switch is turned to intermittent position, the BCM detects a front wiper (intermittent) ON signal by BCM wiper switch reading function.
BCM then sends front wiper (intermittent) request signal over CAN communication lines
- from BCM terminals 39 and 40
- to IPDM E/R terminals 48 and 49.
When BCM determines that combination switch status is front wiper intermittent ON, it performs the following operations.
- BCM detects ON/OFF status of intermittent wiper dial position
- BCM calculates operation interval from wiper dial position and vehicle speed signal received from unified meter and A/C amp. 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 supplies ground to energize the front wiper relay. It then sends auto-stop signal to BCM and conducts intermittent front wiper motor operation.
AUTO STOP OPERATION
When the wiper arms are not located at the base of the windshield and the wiper switch is turned OFF, the wiper motor will continue to operate until the wiper arms reach windshield base. When wiper arms reach base of windshield, front wiper motor terminals P and E are connected.
Ground is supplied
- to terminal 32 of the IPDM E/R
- through front wiper motor terminal P
- through terminal E of the front wiper motor
- through grounds E15 and E24.
The IPDM E/R sends auto stop operation signal to BCM through CAN communication lines.
When BCM receives auto stop operation signal, BCM sends wiper stop signal to IPDM E/R with CAN communication lines. The IPDM E/R then de-energizes the front wiper relay.
Wiper motor will then stop wiper arms at the STOP position.
WASHER OPERATION
When wiper switch is in front wiper washer position, BCM detects front wiper washer signal by BCM wiper switch reading function. Refer to "COMBINATION SWITCH READING FUNCTION".
When the ignition switch is in ON or START position, power is supplied
- through 10 A fuse (No. 47, located in the IPDM E/R)
- through IPDM E/R terminal 44
- to front washer motor terminal +.
When front wiper switch is placed in washer position, ground is supplied
- to front washer motor terminal -
- through combination switch terminal 11
- through combination switch terminal 12
- through grounds M57, M61 and M79.
With power and ground supplied, the front washer motor is operated.
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 temporarily placed in 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.
COMBINATION SWITCH READING FUNCTION
Description
- BCM reads combination switch (wiper) status and controls related systems, such as head lamps and wipers, according to the results.
- BCM reads information of a maximum of 20 switches by combining five output terminals (OUTPUT 1-5) and five input terminals (INPUT 1-5).
Operation Description
- BCM activates transistors of output terminals (OUTPUT 1-5) periodically and allows current to flow in turn.
- If any (1 or more) switches are turned ON, circuit of output terminals (OUTPUT 1-5) and input terminals (INPUT 1-5) becomes active.
- At this time, transistors of output terminals (OUTPUT 1-5) are activated to allow current to flow. When voltage of input terminals (INPUT 1-5) corresponding to that switch changes, interface in BCM detects voltage change and BCM determines that switch is ON.
BCM - Operation Table of Combination Switches
Sample Operation: (When Wiper Switch is Turned ON)
- When wiper switch is turned ON, contact in combination switch turns ON. At this time, if OUTPUT 1 transistor is activated, BCM detects that voltage changes in INPUT 3.
- When OUTPUT 1 transistor is ON, BCM detects that voltage changes in INPUT 3, and judges that front wiper low is ON. Then BCM sends front wiper request signal (LO) to IPDM E/R using CAN communication.
- When OUTPUT 1 transistor is activated again, BCM detects that voltage changes in INPUT 3, and recognizes that wiper switch is continuously ON.
NOTE: Each OUTPUT terminal transistor is activated at 10 ms intervals. Therefore, after switch is turned ON, electrical loads are activated with time delay. This time delay is so short that it cannot be detected by human senses.
Operation Mode
Combination switch reading function has operation modes shown.
1. Normal status
- When BCM is not in sleep status, OUTPUT terminals (1-5) each turn ON-OFF every 10 ms.
2. Sleep status
- When BCM is in sleep status, transistors of OUTPUT 1 stop the output, and BCM enters low current consumption mode. OUTPUT (2, 3, and 4) turn ON-OFF every 10 ms, and only input from light switch system is accepted.
CAN Communication System Description
Refer to Information Bus.