Mirror Heater does not Operate with Rear Defogger Switch [12/2019 - 11/2023]: Procedure

1. Perform the Active Test according to the display on the GTS.

   Body Electrical > Air Conditioner > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Defogger Relay (Rear)	Mirror Heater	OFF or ON	-

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Defogger Relay (Rear)

   Result

   Result	Proceed to
   Mirror heater operation on both mirrors is not normal	A
   Mirror heater operation on RH side mirror is not normal	B
   Mirror heater operation on LH side mirror is not normal	C

Result: 

B 

See step  7

Result: 

C 

See step  9

Result: 

A 

See step  2

1. Check the window defogger system operation.

   Refer to OPERATION CHECK [12/2019 - 11/2023]

   OK

   The window defogger system operates normally.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

GO TO WINDOW DEFOGGER SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 11/2023] 

Result: 

OK 

See step  3

1. Remove the MIR HTR relay from no. 1 engine room relay block and no. 1 junction block assembly.
2. Inspect the MIR HTR relay.
   1. Measure the resistance according to the value(s) in the table below.

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection	Condition	Specified Condition
      3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω
      3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE MIR HTR RELAY 

Result: 

OK 

See step  4

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
   *a	MIR HTR Relay holder terminals

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   MIR HTR relay holder terminal 5 - Body ground	Ignition switch off*1 Always*2	11 to 14 V

   1. *1: for HV Model
   2. *2: for Gasoline Model
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   MIR HTR relay holder terminal 1 - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Remove the DEF relay from No. 1 engine room relay block and No. 1 junction block assembly.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   DEF relay holder terminal 3 - MIR HTR relay holder terminal 2	Always	Below 1 Ω
   DEF relay holder terminal 3 or MIR HTR relay terminal 2 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Disconnect the J31 outer rear view mirror assembly LH connector.
2. Disconnect the J15 outer rear view mirror assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J31-6 (+) - MIR HTR relay holder terminal 3	Always	Below 1 Ω
   J31-6 (+) or MIR HTR relay holder terminal 3 - Body ground	Always	10 kΩ or higher
   J31-11 (E) - Body ground	Always	Below 1 Ω
   J15-6 (+) - MIR HTR relay holder terminal 3	Always	Below 1 Ω
   J15-6 (+) or MIR HTR relay holder terminal 3 - Body ground	Always	10 kΩ or higher
   J15-11 (E) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Remove the MIR HTR relay from the No. 1 engine room relay block and No. 1 junction block assembly.
2. Disconnect the J31 outer rear view mirror assembly LH connector.
3. Disconnect the J15 outer rear view mirror assembly RH connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J15-6 (+) - MIR HTR relay holder terminal 3	Always	Below 1 Ω
   J15-11 (E) - Body ground	Always	Below 1 Ω
   J15-6 (+) or MIR HTR relay holder terminal 3 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  8

Refer to INSPECTION [12/2019 - ]

OK

Outer mirror RH is normal.

Result

Result: 

OK 

REPLACE OUTER REAR VIEW MIRROR ASSEMBLY RH. Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

NG 

REPLACE OUTER MIRROR RH. Refer to  REMOVAL [12/2019 - ] 

1. Remove the MIR HTR relay from the No. 1 engine room relay block and No. 1 junction block assembly.
2. Disconnect the J31 outer rear view mirror assembly LH connector.
3. Disconnect the J15 outer rear view mirror assembly RH connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J31-6 (+) - MIR HTR relay holder terminal 3	Always	Below 1 Ω
   J31-11 (E) - Body ground	Always	Below 1 Ω
   J31-6 (+) or MIR HTR relay holder terminal 3 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  10

Refer to INSPECTION [12/2019 - ]

OK

Outer mirror LH is normal.

Result

Result: 

OK 

REPLACE OUTER REAR VIEW MIRROR ASSEMBLY LH. Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

NG 

REPLACE OUTER MIRROR LH. Refer to  REMOVAL [12/2019 - ]