RX400h · Service Manual BODY

Rear Window Defogger System does not Operate

Circuit diagnosis

DESCRIPTION

  1. The rear defogger & mirror heater switch on the multi-display inputs a request signal to the A/C amplifier (ECU). Then, the A/C amplifier turns ON the RR-DEF relay built into the power distributor in response to the input, thus switching ON the rear defogger. (The deicer and mirror heater also turn ON at the same time)

    HINT:
    The power distributor is built into the J/B No.2.

  1. The RR-DEF relay is built into the J/B No.2. For inspection, use the terminals in the J/B No.2.
  1. If RR-DEF relay is malfunctioning , replace the J/B No.2.

WIRING DIAGRAM

B110872E03

INSPECTION PROCEDURE


1. INSPECT COMMUNICATION LINE

  1. Use the intelligent tester to check for normal function of the multiplex communication system.

    1. (ECU unconnected, communication line malfunctioning) Without DTC B1214, B1215 or B 1262 outputs, proceed to A.

    2. (ECU unconnected, communication line malfunctioning) With DTC B1214, B1215 or B 1262 outputs, proceed to B.



 B
GO TO MULTIPLEX COMMUNICATION SYSTEM
A


2. INSPECT FUSE (HEATER, RR-DEF)

  1. Remove the HEATER fuse from the instrument panel J/B.

  1. Remove the RR-DEF fuse from the FL block.

  1. Check the resistance.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


3. PERFORM ACTIVE TEST

  1. Connect the intelligent tester (with CAN VIN) to the DLC3.

  1. Turn the ignition switch on.

  1. Perform the ACTIVE TEST according to the display on the tester.

A/C amplifier assembly (A/C ECU) 
Item
 Test Details
 Diagnostic Note
DEFOGGER RLY-R
 Operate rear window defogger OFF/ON
 -


NG
Go to step 5
OK


4. CHECK AIR CONDITIONING SYSTEM OPERATE


NG
GO TO AIR CONDITIONING SYSTEM
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

5. INSPECT JUNCTION BLOCK

  1. I037288E04
    Check the voltage of the terminal of the J/B.

    Standard voltage:
    Tester Connection
    		 Switch Position
    		 Specified Condition
    2H-12 - Body Ground
    		 Ignition switch ON
    		 10 to 14 V
    2H-12 - Body Ground
    		 Ignition switch OFF
    		 Below 1 V
    2B-8 - Body Ground
    		 Always
    		 10 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK


6. INSPECT JUNCTION BLOCK (MODE MONITOR TERMINAL)

  1. B069895E01
    Check the voltage of the terminal to the following condition.
    1. Engine running.
    1. A/C switch is OFF.
    1. Rear defogger and deicer switch is ON.

    Result:
    Result
    		 Proceed to
    More than 5 V
    		 A
    Below 2 V
    		 B



B
Go to step 12
A


7. INSPECT JUNCTION BLOCK (RR-DEF RELAY)

  1. Remove the junction block No.2.

  1. I037288E04
    Connect the battery positive (+) lead to terminal 2B-8 and battery negative (-) terminal lead to terminal 2H-12, 2B-7 and 2H-11.

  1. Check the voltage of the RR-DEF relay terminals.

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    2B-7 - 2H-12
    		 Always
    		 Below 1 V

  1. Connect another battery positive (+) lead to the terminal 2H-12.

  1. Check the voltage of the RR-DEF relay terminals.

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    2B-7 - 2H-12
    		 Ignition switch ON
    		 Below 1 V
    2B-7 - 2H-12
    		 Ignition switch OFF
    		 10 to 14 V



NG
REPLACE JUNCTION BLOCK
OK


8. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

  1. E109218E27
    Disconnect the A11 connector.

  1. Measure the voltage according to the value(s) in the table below.

Standard voltage:
Tester connection
 Condition
 Specified condition
A11-19 (DFG) - Body ground
 Ignition switch: ON
 10 to 14 V
A11-19 (DFG) - Body ground
 Ignition switch: OFF
 Below 1 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


9. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY
E109265E32

  1. Connect the A11 connector.

  1. Connect the intelligent tester to the DLC3.

  1. Measure the voltage according to the value(s) in the table below.

Standard voltage:
Tester connection
 Intelligent tester condition
 Specified condition
A11-19 (DFG) - Body ground
 ACTIVE TEST: ON (*1)
 10 to 14 V
A11-19 (DFG) - Body ground
 ACTIVE TEST: OFF (*1)
 Below 1 V


HINT:
*1: Perform the ACTIVE TEST according to the display on the tester.
A/C amplifier assembly (A/C ECU) 
Item
 Test Details
 Diagnostic Note
DEFOGGER RLY-R
 Operate rear window defogger OFF/ON
 -



NG
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
OK


10. INSPECT REAR WINDOW DEFOGGER WIRE

NOTICE:
  1. When cleaning the glass, wipe the glass along the wire using a soft and dry cloth. Take care not to damage the wires.
  2. Do not use detergents or glass cleaners that have abrasive ingredients.

  3. B106755E01
    When measuring voltage, wrap a piece of tin foil around the tip of the negative tester probe and press the foil against the wire with your finger, as shown in the illustration.

  1. Turn the ignition switch on.

  1. Turn the defogger switch ON.

  1. B106756E01
    Check the voltage at the center of each defogger wire, as shown in the illustration.

    Standard voltage:
    Voltage
    		 Criteria
    Approx .5 V
    		 Wire is not broken
    Approx. 10 or 0 V
    		 Wire is broken

    HINT:
    If there is approximately 10 V, the wire may be broken between the center of the wire and the wire end on the battery side. If there is no voltage, the wire may be broken between the center of the wire and the end on the ground side.

  1. Place the voltmeter positive (+) lead against the defogger wire on the battery side.

  1. Place the voltmeter negative (-) lead with the foil strip against the wire on the ground side.

  1. Slide the positive (+) lead from the battery side to the ground side.

  1. B106757E01
    The point where the voltage drops from approximately 10 V to 0 V is where the defogger wire is broken.

    HINT:
    If the defogger wire is not broken, the voltmeter indicates 0 V at the positive (+) end of the defogger wire but gradually increases to approximately 12 V as the meter probe moves to the other end.



 NG
REPAIR REAR WINDOW DEFOGGER WIRE
OK


11. CHECK WIRE HARNESS (REAR WINDOW DEFOGGER - JUNCTION BLOCK NO.2)

  1. B069898E02
    Disconnect the N6, N5 defogger and 2B J/B connectors.

  1. Check the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    N6-1 - 2B-7
    		 Below 1 Ω
    N6-1 -Body ground
    		 10 kΩ or higher
    N5-1 - Body ground
    		 Below 1 Ω
    N5-1 - 2B-7
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE NOISE FILTER

12. CHECK WIRE HARNESS (REAR WINDOW DEFOGGER - JUNCTION BLOCK NO.2)

  1. B069898E02
    Disconnect the N6, N5 defogger and 2B J/B connectors.

  1. Check the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    N6-1 - 2B-7
    		 Below 1 Ω
    N6-1 -Body ground
    		 10 kΩ or higher
    N5-1 - Body ground
    		 Below 1 Ω
    N5-1 - 2B-7
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


13. INSPECT JUNCTION BLOCK (RR-DEF RELAY)

  1. Remove the junction block No.2.

  1. I037288E04
    Connect the battery positive (+) lead to terminal 2B-8 and battery negative (-) terminal lead to terminal 2H-12, 2B-7 and 2H-11.

  1. Check the voltage of the RR-DEF relay terminals.

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    2B-7 - 2H-12
    		 Always
    		 Below 1 V

  1. Connect another battery positive (+) lead to the terminal 2H-12.

  1. Check the voltage of the RR-DEF relay terminals.

    Standard voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    2B-7 - 2H-12
    		 Ignition switch ON
    		 10 to 14 V
    2B-7 - 2H-12
    		 Ignition switch OFF
    		 Below 1 V



NG
REPLACE JUNCTION BLOCK
OK

REPLACE NOISE FILTER


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