Pinpoint Test U: The Heated Seat Is Inoperative/Does Not Operate Correctly - Left Rear
Seats
Pinpoint Tests
Pinpoint Test U: The Heated Seat is Inoperative/Does Not Operate Correctly - Left Rear
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The heated seat module receives battery voltage on circuit CBP35 (YE/GY) and ignition voltage on circuit SBB05 (GY/RD), and is supplied ground on circuit GD133 (BK). When the left rear heated seat control switch is pressed with the ignition switch in RUN or START, a ground is supplied on circuit CHS46 (YE/GN) to command the system on or off in high heat mode or circuit CHS47 (VT/GN) to command the system on or off in low heat mode. When commanded on, voltage is supplied to the heated seat switch from the heated seat module on either circuit CHS48 (YE) (high heat mode) or circuit CHS49 (VT) (low heat mode) illuminating the switch indicator. The heated seat module also supplies voltage to the cushion and backrest heater mats on circuit CHS39 (GN/BU) and ground to the heater mats on circuit GD147 (BK/VT). The cushion and backrest heater mats are connected in series and operate together. Temperature is maintained by the heated seat module using a sensor contained within the cushion heater mat. The heated seat module monitors the temperature sensor on circuit VHS42 (GN) for adjusting the current flow to the heater mats and uses a ground supplied on circuit RHS41 (GN/BN). The heated seat module is designed to remain on, heating the seat and maintaining temperature until switched off or the ignition voltage is switched OFF.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat switch
- Heater mat
- Heated seat module
PINPOINT TEST U: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - LEFT REAR
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U1 CHECK THE REAR HEATED SEAT CIRCUIT FOR VOLTAGE
- Disconnect: Rear Heated Seat Module C3162.
- Measure the voltage between rear heated seat module C3162-1, circuit SBB05 (GY/RD) harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to U2.
No
REPAIR the circuit. TEST the system for normal operation.
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U2 CHECK THE LEFT REAR HEATED SEAT FEED CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Left Rear Cushion Heater Mat C3167.
- Measure the resistance between:
- left rear seat cushion heater mat C3167-1, circuit CHS39 (GN/BU), harness side and heated seat module C3162-9, circuit CHS39 (GN/BU), harness side.
- left rear seat cushion heater mat C3167-1, circuit CHS39 (GN/BU), harness side and ground.
- Is the resistance less than 5 ohms between C3162-9 and C3167-1 and greater than 10,000 ohms between C3167-9 and ground?
Yes
GO to U3.
No
REPAIR the circuit. TEST the system for normal operation.
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U3 CHECK THE LEFT REAR HEATED SEAT SENSOR CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- heated seat cushion heater mat C3167-2, circuit VHS42 (GN), harness side and heated seat module C3162-10, circuit VHS42 (GN), harness side.
- heated seat cushion heater mat C3167-2, circuit VHS42 (GN), harness side and ground.
- Is the resistance less than 5 ohms between C3162-10 and C31672 and greater than 10,000 ohms between C3167-2 and ground?
Yes
GO to U4.
No
REPAIR the circuit. TEST the system for normal operation.
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U4 CHECK THE HEATED SEAT SENSOR RETURN CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- left rear seat cushion heater mat C3167-3, circuit RHS41 (GN/BN), harness side and heated seat module C3162-13, circuit RHS41 (GN/BN), harness side.
- left rear seat cushion heater mat C3167-3, circuit RHS41 (GN/BN), harness side and ground.
- Is resistance less than 5 ohms between C3162-13 and C3167-3 and greater than 10,000 ohms between the C3167-3 and ground?
Yes
GO to U5.
No
REPAIR the circuit. TEST the system for normal operation.
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U5 CHECK THE LEFT REAR CUSHION CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between left rear seat cushion heater mat C3167, harness side and ground using the following chart.
- Is voltage present on any circuits?
Yes
REPAIR the affected circuit. TEST the system for normal operation.
No
GO to U6.
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U6 CHECK THE BACKREST HEATER MAT GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Left Rear Seat Backrest Heater Mat C3168.
- Measure the resistance between left rear seat backrest heater mat C3168-1, circuit GD147 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to U7.
No
REPAIR the circuit. TEST the system for normal operation.
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U7 CHECK THE CUSHION HEATER MAT AND SENSOR FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between:
- left rear seat cushion heater mat C3167 pin 1, component side and ground.
- left rear seat cushion heater mat C3167 pin 2, component side and ground.
- Is voltage present on either circuit?
Yes
INSTALL a new cushion heater mat. TEST the system for normal operation.
No
GO to U8.
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U8 CHECK THE CUSHION HEATER MAT FOR AN OPEN AND A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- left rear seat cushion heater mat C3167 pin 1, component side and ground.
- left rear seat cushion heater mat C3167 pin 1 and pin 4, component side.
- Is resistance greater than 10,000 ohms between the left rear seat cushion heater mat and ground; and between 1.6 and 2.2 ohms between the left rear seat cushion heater mat pins 1 and 4?
Yes
GO to U9.
No
INSTALL a new cushion heater mat. TEST the system for normal operation.
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U9 CHECK THE BACKREST HEATER MAT FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- left rear seat backrest heater mat connector pin 2, component side and ground.
- left rear seat backrest heater mat connector pin 2 and pin 1, component side.
- Is resistance greater than 10,000 ohms between the left rear seat backrest heater mat and ground; and between 1.6 and 2.2 ohms between the left rear seat backrest heater mat pins?
Yes
GO to U10.
No
INSTALL a new backrest heater mat. TEST the system for normal operation.
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U10 CHECK THE HEATER MAT CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Measure resistance between:
- left rear seat cushion heater mat C3167-4, circuit CHS40 (GY/VT), harness side and left rear seat backrest heater mat C3168-2, circuit CHS40 (GY/VT), harness side.
- left rear seat cushion heater mat C3167-4, circuit CHS40 (GY/VT), harness side and ground.
- Is resistance less than 5 ohms?
Yes
GO to U11.
No
REPAIR the circuit. TEST the system for normal operation.
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U11 CHECK THE HEATER MAT TEMPERATURE SENSOR FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- left rear seat cushion heater mat C3167 pin 2 and pin 3, component side.
- left rear seat cushion heater mat C3167 pin 2, component side and ground.
- Is the resistance less than 300,000 ohms and greater than 50 ohms between left rear seat cushion heater mat; and greater than 10,000 ohms between left rear seat cushion heater mat and ground?
Yes
GO to U12.
No
INSTALL a new cushion heater mat. TEST the system for normal operation.
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U12 CHECK HEATED SEAT SWITCH CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: Left Rear Heated Seat Switch C3340.
- Ignition ON.
- Measure the voltage between:
- heated seat module C3162-11, circuit CHS46 (YE/GN), harness side and ground.
- heated seat module C3162-12, circuit CHS47 (VT/GN), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to U13.
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U13 CHECK THE HEATED SEAT SWITCH CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- heated seat module C3162-11, circuit CHS46 (YE/GN), harness side and ground.
- heated seat module C3162-12, circuit CHS47 (VT/GN), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to U14.
No
REPAIR the circuit. TEST the system for normal operation.
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U14 CHECK FOR A SHORT BETWEEN HEATED SEAT SWITCH CIRCUITS
- Measure the resistance between heated seat module C3162-11, circuit CHS46 (YE/GN), harness side and heated seat module C3162-12, circuit CHS47 (VT/GN), harness side.
- Is resistance greater than 10,000 ohms?
Yes
GO to U15.
No
REPAIR the shorted circuits. TEST the system for normal operation.
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U15 CHECK THE HEATED SEAT SWITCH CIRCUITS FOR AN OPEN
- Measure the resistance between:
- heated seat module C3162-11, circuit CHS46 (YE/GN), harness side and left rear heated seat switch C3340-6, circuit CHS46 (YE/GN), harness side.
- heated seat module C3162-12, circuit CHS47 (VT/GN), harness side and left rear heated seat switch C3340-2, circuit CHS47 (VT/GN), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to U16.
No
REPAIR the circuit. TEST the system for normal operation.
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U16 CHECK THE HEATED SEAT SWITCH GROUND CIRCUIT FOR AN OPEN
- Measure resistance between left rear heated seat switch C3340-1, circuit GD133 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to U17.
No
REPAIR the circuit. TEST the system for normal operation.
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U17 CHECK THE REAR HEATED SEAT OPERATION USING ANOTHER SWITCH
- Connect the right rear heated seat switch to the left rear heated seat switch connector.
- Ignition ON.
- Check the left rear heated seat operation.
- Does the left rear heated seat operate correctly using the other switch?
Yes
INSTALL a new heated seat switch. REFER to Heated Seat Switch - Rear Heated Seat Switch - Rear. TEST the system for normal operation.
No
INSTALL a new heated seat module. REFER to Heated Seat Module - Rear Heated Seat Module - Rear. TEST the system for normal operation.
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