Diagnosis Procedure

Regarding Wiring Diagram information, refer to WIRING DIAGRAM .

1. CHECK POWER CIRCUIT
   
   
   1. Turn ignition switch OFF.
   2. Remove the heated steering wheel switch. Refer to REMOVAL AND INSTALLATION .
   3. Turn ignition switch ON.
   4. Check voltage between heated steering wheel switch harness connector terminals.

      Connector	Terminal		Voltage (Approx.)
      	+	-
      M48	1	2	Battery voltage

   Is the inspection result normal?

   YES 

   GO TO STEP 2  .

   NO 

   GO TO STEP   7  .

2. CHECK GROUND CIRCUIT
   
   
   1. Turn ignition switch OFF.
   2. Disconnect heated steering wheel switch connector.
   3. Check continuity between heated steering wheel switch harness connector terminal and ground.

   Connector	Terminal	Ground	Continuity
   M48	6		Yes

   Is the inspection result normal?

   YES 

   GO TO STEP 3  .

   NO 

   Repair harness or connector.

3. CHECK HARNESS BETWEEN HEATED STEERING RELAY AND HEATED STEERING WHEEL SWITCH
   
   
   1. Disconnect heated steering relay connector.
   2. Check continuity between heated steering relay harness connector terminal and heated steering wheel switch harness connector terminal.

      Heated steering relay		Heated steering wheel switch		Continuity
      Connector	Terminal	Connector	Terminal
      M90	5	M48	5	Yes

   3. Check continuity between heated steering relay harness connector terminal and ground.

      Connector	Terminal	Ground	Continuity
      M90	5		No

   Is the inspection result normal?

   YES 

   GO TO STEP 4  .

   NO 

   Repair harness or connector.

4. CHECK HEATED STEERING RELAY
   
   

   Check heated steering relay. Refer to COMPONENT INSPECTION (HEATED STEERING RELAY) .

   Is the inspection result normal?

   YES 

   GO TO STEP 5  .

   NO 

   Replace heated steering relay.

5. CHECK BATTERY POWER
   
   

   Check the following:

   • Battery
   • Harness for open or short between battery and 10A fuse (No. 74)
   • 10A fuse (No. 74)
   • Harness for open or short between 10A fuse (No. 74) and heated steering wheel relay

   Is the inspection result normal?

   YES 

   GO TO STEP 6  .

   NO 

   Repair harness or connector.

6. CHECK HARNESS BETWEEN A/C AUTO AMP. AND HEATED STEERING WHEEL RELAY
   
   
   1. Check continuity between A/C auto amp. harness connector terminal and heated steering wheel relay harness connector terminal.

      A/C auto amp.		Heated steering wheel relay		Continuity
      Connector	Terminal	Connector	Terminal
      M50	20	M90	2	Yes

   2. Check continuity between A/C auto amp. harness connector terminal and ground.

      A/C auto amp.		Ground	Continuity
      Connector	Terminal
      M50	20		No

   Is the inspection result normal?

   YES 

   GO TO STEP 9  .

   NO 

   Repair harness or connector.

7. CHECK HARNESS BETWEEN A/C AUTO AMP. AND HEATED STEERING WHEEL SWITCH
   
   
   1. Check continuity between A/C auto amp. harness connector terminal and heated steering wheel switch harness connector terminal.

      A/C auto amp.		Heated steering wheel switch		Continuity
      Connector	Terminal	Connector	Terminal
      M50	8	M48	1	Yes

   2. Check continuity between A/C auto amp. harness connector terminal and ground.

      A/C auto amp.		Ground	Continuity
      Connector	Terminal
      M50	8		No

   Is the inspection result normal?

   YES 

   GO TO STEP 8  .

   NO 

   Repair or replace harness or connector.

8. CHECK GROUND CIRCUIT
   
   
   1. Disconnect heated steering wheel switch.
   2. Check continuity between heated steering wheel switch harness connector terminal and ground.

   Connector	Terminal	Ground	Continuity
   M48	2		Yes

   Is the inspection result normal?

   YES 

   GO TO STEP 9  .

   NO 

   Repair or replace harness or connector.

9. CHECK HEATED STEERING WHEEL SWITCH
   
   

   Check heated steering wheel switch. Refer to COMPONENT INSPECTION (HEATED STEERING WHEEL SWITCH) .

   Is the inspection result normal?

   YES 

   Replace A/C auto amp. Refer to REMOVAL AND INSTALLATION

   NO 

   Replace heated steering wheel switch. Refer to REMOVAL AND INSTALLATION .