Wiper and Washer Systems: Description and Operation
System Description- Both front wiper relays are located in the IPDM E/R (intelligent power distribution module engine room).
- The wiper switch (combination switch) is composed of a combination of 5 output terminals and 5 input terminals. Terminal combination status is read by the BCM (body control module) when the wiper switch is turned ON.
- BCM controls front wiper LO, HI, and INT (intermittent) operation.
- IPDM E/R operates the 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 70, and
- through 30 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. 59, located in the fuse and relay box)
- to BCM terminal 38.
Ground is supplied
- to BCM terminal 67 and
- to combination switch terminal 12
- through grounds M57, M61 and M79, and
- to IPDM E/R terminals 38 and 59 and
- to front wiper motor terminal 1
- through grounds E9, 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 the low position, the BCM detects a low speed wiper ON request through the combination switch (wiper switch) reading function.
The BCM then sends a front wiper (low) request signal over CAN communication lines
- from BCM terminals 39 and 40
- to IPDM E/R terminals 39 and 40.
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 32
- to front wiper motor terminal 3.
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 the high position, the BCM detects a high speed wiper ON request through the combination switch (wiper switch) reading function.
The BCM then sends a front wiper (high) request signal over CAN communication lines
- from BCM terminals 39 and 40
- to IPDM E/R terminals 39 and 40.
When the IPDM E/R receives a 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 35
- to front wiper motor terminal 2.
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 the ON or START position, and the front wiper switch is turned to an intermittent position, the BCM detects a front wiper (intermittent) ON request through the combination switch (wiper switch) reading function.
The BCM then sends a front wiper (intermittent) request signal over CAN communication lines
- from BCM terminals 39 and 40
- to IPDM E/R terminals 39 and 40.
When the 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 through CAN communications.
- BCM sends front wiper request signal (INT) to IPDM E/R at calculated operation interval.
When the IPDM E/R receives a front wiper request signal (INT), it supplies ground to energize the front wiper relay. It then sends an auto-stop signal to the 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 the windshield base. When the wiper arms reach the base of windshield, front wiper motor terminals 6 and 1 are connected.
Ground is supplied
- to IPDM E/R terminal 43
- through front wiper motor terminal 6
- through front wiper motor terminal 1
- through grounds E9, E15 and E24.
The IPDM E/R sends an auto stop operation signal to the BCM through CAN communication lines.
When the BCM receives an auto stop operation signal, the BCM sends wiper stop signal to the IPDM E/R over
CAN communication lines. The IPDM E/R then de-energizes the front wiper relay.
The wiper motor will then stop the wiper arms at the STOP position.
FRONT WASHER OPERATION
When the ignition switch is in the ON or START position, and the front washer switch is OFF, the front washer motor is supplied power
- through 10 A fuse (No. 9, located in the fuse block J/B)
- to front washer motor terminal 1.
When the front wiper switch is in the front washer position, the BCM detects a front washer signal request through the combination switch (wiper switch) reading function.
Combination switch ground is supplied
- to front washer motor terminal 2
- through combination switch (wiper switch) terminal 11
- through combination switch (wiper switch) terminal 12
- through grounds M57, M61 and M79.
With ground supplied, the front washer motor operates.
When the BCM detects that front washer motor has operated for 0.4 seconds or longer, the BCM uses CAN communication and sends a wiper request signal to the IPDM E/R for low speed operation of wipers.
When the BCM detects that the 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
The BCM includes fail-safe function to prevent malfunction of electrical components controlled by CAN communications if a malfunction in CAN communications occurs.
The BCM uses CAN communications to stop output of electrical components it controls.
Until the ignition switch is turned off, the front wiper system 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, the 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 status, and controls related systems such as headlamps and wipers, according to the results.
- BCM reads information for 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, the 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 the input terminal (INPUT 1-5) corresponding to that switch changes, the interface in the BCM detects a voltage change, and the BCM determines that the switch is ON.
BCM - Operation Table of Combination Switches
Sample Operation: (When Wiper Switch is Turned ON)
- When the wiper switch is turned ON, contact in the combination switch turns ON. At this time if OUTPUT 1 transistor is activated, the BCM detects that voltage changes in INPUT 3.
- When the OUTPUT 1 transistor is ON, the BCM detects that voltage changes in INPUT 3, and judges that front wiper low is ON. Then the BCM sends a front wiper request signal (LO) to the IPDM E/R using CAN communication.
- When OUTPUT 1 transistor is activated again, BCM detects that voltage changes in INPUT 3, and recognizes that the wiper switch is continuously ON.
NOTE: Each OUTPUT terminal transistor is activated at 10 ms intervals. Therefore, after the 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
The combination switch reading function has the 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".