SEAT WARMER SYSTEM OPERATES CONSTANTLY [SEAT WARMER SYSTEM]

id0903m2970900

Description	The seat warmer warms the seat even though the seat warmer switch is turned off.
Possible Causes	•  Seat warmer switch malfunction •  Seat warmer control unit malfunction •  Short to power supply in wiring harness between the following terminals: ―  Seat warmer control unit terminal I and indicator unit terminal D

Diagnostic Procedure

Step	Inspection		Action
1	DETERMINE IF MALFUNCTION CAUSE IS SEAT WARMER SWITCH •  Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) •  Disconnect the indicator unit connector. •  Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) •  Switch the ignition ON (engine off or on). •  Does the seat warmer system operate?	Yes	Go to the next step.
		No	Replace the indicator unit. (See INDICATOR UNIT REMOVAL/INSTALLATION.)
2	DETERMINE IF MALFUNCTION CAUSE IS SEAT WARMER CONTROL UNIT •  Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) •  Disconnect the seat warmer control unit connector. •  Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) •  Switch the ignition ON (engine off or on). •  Measure the voltage at seat warmer control unit terminal I (vehicle wiring harness side). •  Is the voltage 1.0 V or more?	Yes	•  Refer to the wiring diagram and verify if there is a common connector between the following terminals. ―  Seat warmer control unit terminal I and indicator unit terminal D If there is a common connector: •  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location. •  Repair or replace the wiring harness which is shorted to the power supply. If there is no common connector: •  Repair or replace the wiring harness which is shorted to the power supply. •  Go to the next step.
		No	Replace the seat warmer control unit, then go to the next step. (See SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION.)
3	VERIFY IF MALFUNCTION CAUSE IS CORRECTED •  Reconnect all the disconnected connectors. •  Switch the ignition ON (engine off or on). •  Operate the seat warmer switch to turn on the seat warmer system. •  Does the seat warmer system operate normally?	Yes	Troubleshooting completed. (Explain the contents of the servicing to the customer.)
		No	Verify the malfunction symptom in the symptom troubleshooting chart and perform the other applicable malfunction diagnosis. (See SYMPTOM TROUBLESHOOTING [SEAT WARMER SYSTEM].)