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Home >> Infiniti Truck >> 2004 >> FX45 AWD V8-4.5L (VK45DE) >> Repair and Diagnosis >> Wiper and Washer Systems >> Description and Operation >> Front Wiper and Washer System >> System Description

System Description

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.

Power is supplied at all times
- through 50 A fusible link (letter M, located in fusible link box.)
- to BCM terminal 55,
- through 15 A fuse [No. 22, located in fuse block (J/B)]
- to BCM terminal 42,
- through 30 A fuse [No. 73, located in IPDM E/R (intelligent power distribution module engine room)]
- to front wiper relay [built in IPDM E/R (intelligent power distribution module engine room)]
- through 15 A fuse [No. 78, located in IPDM E/R (intelligent power distribution module engine room)]
- through 10 A fuse [No. 71, located in IPDM E/R (intelligent power distribution module engine room)]
- to IPDM E/R (CPU).

When the ignition switch ON or START position, power is supplied
- through 15 A fuse [No. 1, located in fuse block (J/B)]
- to BCM terminal 38 and
- through ignition relay [built in IPDM E/R (intelligent power distribution module engine room)]
- to front wiper relay [built in IPDM E/R (intelligent power distribution module engine room)] and
- to front wiper high relay [built in IPDM E/R (intelligent power distribution module engine room)] and
- through 10 A fuse [No. 84, located in IPDM E/R (intelligent power distribution module engine room)]
- through IPDM E/R terminal 44
- to front washer motor terminal 1.

Ground is supplied
- to BCM terminals 49 and 52
- through body grounds M35, M45 and M85,
- to IPDM E/R terminals 38 and 60
- through body grounds E21, E50 and E51.
- to combination switch (wiper switch) terminal 12
- through body grounds M35, M45 and M85.

LOW SPEED WIPER OPERATION
When wiper switch is in LO position, BCM detects low speed wiper ON signal by BCM wiper switch reading function.
BCM sends front wiper request signal (LO) with CAN communication line
- from BCM terminals 39 and 40
- to IPDM E/R terminals 48 and 49.

When IPDM E/R receives front wiper request signal (LO), it turns ON front wiper relay (built in IPDM E/R), power is supplied
- to front wiper motor terminal 1
- through IPDM E/R terminal 21 and front wiper relay and front wiper HI relay.

Ground is supplied
- to front wiper motor terminal 2
- through body grounds E21, E50 and E51.

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

HI SPEED WIPER OPERATION
When wiper switch is in HI position, BCM detects high speed wiper ON signal by BCM wiper switch reading function.
BCM sends front wiper request signal (HI) with CAN communication line
- from BCM terminals 39 and 40
- to IPDM E/R terminals 48 and 49.

When IPDM E/R receives front wiper request signal (HI), it turns ON front wiper relay (built in IPDM E/R), power is supplied
- to front wiper motor terminal 4
- through IPDM E/R terminal 31 and front wiper relay and front wiper HI relay.

Ground is supplied
- to front wiper motor terminal 2
- through body grounds E21, E50 and E51.

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

INTERMITTENT OPERATION
Wiper intermittent operation delay interval is determined from a combination of 3 switches (intermittent operation dial position 1, intermittent operation dial position 2, and intermittent operation dial position 3) and vehicle speed signal.
During each intermittent operation delay interval, BCM sends front wiper request signal to IPDM E/R.




Wiper Dial Position Setting
Example: For wiper dial position 1...
Using combination switch reading function, BCM detects ON/OFF status of intermittent operation dial positions 1, 2, and 3.
When combination switch status is as listed below, BCM determines that it is wiper dial position 1.
- Intermittent operation dial position 1: ON (Combination switch output 3 and input 1 are performing.)
- Intermittent operation dial position 2: ON (Combination switch output 5 and input 1 are performing.)
- Intermittent operation dial position 3: ON (Combination switch output 4 and output 2 are performing.)

BCM determines front wiper intermittent operation delay interval from wiper dial position 1 and vehicle speed, and sends wiper request signal (INT) to IPDM E/R.

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 21 of the IPDM E/R
- to front wiper motor terminal 1, in order to continue wiper motor operation at low speed.

When wiper arms reach base of windshield, front wiper motor terminals 5 and 2 are connected, and Ground is supplied
- to terminal 32 of IPDM E/R
- through front wiper motor terminals 5 and 2
- through body grounds E21, E50 and E51.

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 wiper switch is in front wiper washer position with ignition switch on, BCM detects front wiper switch is on the washer position by BCM wiper switch reading function (Refer to "COMBINATION SWITCH READING FUNCTION" ), combination switch (wiper switch) ground is supplied
- to front washer motor terminal 2
- through combination switch (wiper switch) terminal 11
- to combination switch (wiper switch) terminal 12
- through body grounds M35, M45 and M85

With ground supplied, front washer motor is operated.
When BCM detects that front washer motor has operated for 0.4 seconds or linger, BCM operates front wiper motor for low speed.
When BCM detects washer switch is OFF, low speed operation cycles approximately 3 times and 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
IPDM E/R includes a fail-safe function to prevent malfunction of electrical components controlled by CAN communications in CAN communications occurs.
When fail-safe status is initiated, IPDM E/R remains in steady unit signals are received.

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, 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
- BCM reads operation status of combination switch using combinations shown in table.




Sample operation: (When wiper switch 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. But 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 and 5) 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.
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