INSPECTION PROCEDURE
1: Power supply circuit check
COMMENTS ON TROUBLE SYMPTOM
If the odometer and trip meter is not displayed or no needle meters work, power supply
to the heated seat control unit, or the heated seat control unit itself may have a problem.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Malfunction of heated seat relay (second)
Malfunction of heated seat control unit
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STEP 1. Voltage measurement at the heated seat control unit
connector
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the LOCK (OFF) position.
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(3)Measure the voltage between the heated seat control unit connector (+B
terminal) and the body earth.
OK: System voltage
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Q.
Is the check result normal?
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 Go to Step 6.
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 Go to Step 2.
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STEP 2. Check the heated seat relay (second)
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Refer to check the heated seat relay (second) (Refer to GROUP 00 - How to Use
Troubleshooting/Inspection Service Points, Relay Inspection).
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Q.
Is the check result normal?
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Go to Step 3.
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Replace the heated seat relay (second).
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STEP 3. Voltage measurement at the heated seat relay (second) connector
(power supply line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Check the voltage between the heated seat relay (second) connector (fusible link
line) and body earth.
OK: System voltage
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(3)Turn the ignition switch to the ON position.
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(4)Check the voltage between the heated seat relay (second) connector (IG2 line) and
body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 4.
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Repair the wiring harness.
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STEP 4. Resistance measurement at the heated seat relay (second) connector
(earth line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Continuity between heated seat relay (second) connector (earth line) and body earth
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the wiring harness.
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STEP 5. Check of open circuit in +B line between the heated
seat relay (second) connector and heated seat control unit connector
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Cope with Intermittent Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 6. Voltage measurement at the heated seat control unit connector
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the ON position.
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(3)Measure the voltage between the heated seat control unit connector (IG terminal)
and the body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 8.
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Go to Step 7.
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STEP 7. Check of open circuit in IG line between the ignition switch
(IG1) and heated seat control unit connector
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 8. Resistance measurement at the heated seat control unit connector
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the heated seat control unit connector (E terminal)
and the body earth.
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 10.
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Go to Step 9.
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STEP 9. Check of open circuit in E line between heated seat control
unit connector and body earth
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Repair the connector(s) or wiring harness.
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STEP 10. Retest the system
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Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent
Malfunction).
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Replace the heated seat control unit (Refer to  ).
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