Pinpoint Test K: The Heated Seat Is Inoperative - Passenger Seat Does Not Heat But The Heated Seat Indicator Illuminates When P
Seats
Pinpoint Tests
Pinpoint Test K: The Heated Seat is Inoperative - Passenger Seat Does Not Heat But the Heated Seat Indicator Illuminates When Pressed
Normal Operation
The HVAC module includes the heated seat switch buttons and indicators. The heated seat system will function when the HVAC module is on or off. There is a relay box located behind the headlamp switch area containing 2 micro relays for the driver and passenger heated seats. Battery voltage from circuit 1048 (LB/WH) is supplied to the coil and switch side of the passenger heated seat relay. When the ignition switch is ON and the engine running, ground is supplied to the passenger heated seat relay coil from the passenger heated seat switch in the HVAC module to energize the relay. This closes the relay switch supplying voltage to passenger seat cushion heater mat from circuit 2124 (YE/LB). The cushion and backrest heater mats are connected in series by circuit 2126 (GY/LB) and ground is supplied to the backrest heater mat circuit 1205 (BK), completing the heater mat circuit to heat the driver seat. If the heated seat switch is on when the ignition switch is turned OFF, the heated seat switch will be on when the ignition switch is turned back ON.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat switch (part of HVAC module)
- Heated seat relay
- Cushion heater mat
- Backrest heater mat
PINPOINT TEST K: THE HEATED SEAT IS INOPERATIVE - PASSENGER SEAT DOES NOT HEAT BUT THE HEATED SEAT INDICATOR ILLUMINATES WHEN PRESSED
WARNING: Remove restraint system diagnostic tools from the vehicle prior to road testing. If tools are not removed, the supplemental restraint system (SRS) device may not deploy in a crash. Failure to follow this instruction may result in serious personal injury or death in a crash and possibly violate vehicle safety standards.
NOTICE: Do not install a new heater mat on a front passenger seat cushion. If a new cushion heater mat is needed on the front passenger seat, an Occupant Classification Sensor (OCS) service kit equipped with a heater mat must be installed. Failure to follow this instruction may result in incorrect operation of the OCS system. Refer to Air Bag Systems for the Occupant Classification Sensor Removal and Installation procedure.
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTICE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test. Inspection and Verification
NOTE: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition switch is ON.
NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
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K1 CHECK CIRCUIT 2124 (YE/LB) FOR VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C337.
- Connect: Restraint System Diagnostic Service Tool 418-133 to Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Heated Seat C334.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
- Connect the battery ground cable.
- Ignition ON.
- Measure voltage between passenger heated seat C334-1 circuit 2124 (YE/LB), harness side and ground.
- Is voltage greater than 10 volts when the heated seat switch is depressed and 0 volt when the switch is off?
Yes
GO to K6.
No
GO to K2.
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K2 CHECK THE HEATED SEAT RELAY
- Ignition OFF.
- Swap the passenger heated seat relay with the driver heated seat relay.
- Ignition ON.
- Does the seat heat when the heated seat switch is depressed?
Yes
INSTALL a new heated seat relay. TEST the system for normal operation.
DISCONNECT the battery ground cable. DISCONNECT the Restraint System Diagnostic Service Tool from passenger seat side air bag module C337. CONNECT passenger seat side air bag module C337. REPOWER the SRS. REFER to Air Bag Systems.
No
GO to K3.
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K3 CHECK VOLTAGE TO THE HEATED SEAT RELAY
- Ignition OFF.
- Disconnect: Heated Seat Relay (Passenger).
- Measure voltage between:
- passenger heated seat relay socket pin 1, circuit 1048 (LB/WH) and ground.
- passenger heated seat relay socket pin 3, circuit 1048 (LB/WH) and ground.
- Are both voltages greater than 10 volts?
Yes
GO to K4.
No
REPAIR the circuit. TEST the system for normal operation.
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K4 CHECK CIRCUIT 2124 (YE/LB) FOR AN OPEN
- Measure resistance between passenger heated seat relay socket pin 5, circuit 2124 (YE/LB) and passenger cushion heater mat C334-1, circuit 2124 (YE/LB), harness side.
- Is resistance less than 5 ohms?
Yes
GO to K5.
No
REPAIR the circuit TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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K5 CHECK HEATED SEAT REQUEST CIRCUIT VOLTAGE
- Connect: Passenger Heated Seat Relay.
- Disconnect: HVAC Module C294a.
- Measure voltage between HVAC module C294a-13, circuit 2119 (DG/VT), harness side and ground.
- Is voltage greater than 10 volts?
Yes
INSTALL a new HVAC module.
No
REPAIR the circuit. TEST the system for normal operation.
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K6 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
- Ignition OFF.
- Disconnect: Passenger Heated Seat C335.
- Measure resistance between passenger seat C335-2 circuit 1205 (BK), harness side and ground.
- Is resistance less than 5 ohms?
Yes
GO to K7.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable. DISCONNECT the Restraint System Diagnostic Service Tool from passenger seat side air bag module C337. CONNECT passenger seat side air bag module C337. REPOWER the SRS. REFER to Air Bag Systems.
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K7 CHECK THE CUSHION HEATER MAT FOR AN OPEN
- Measure resistance between passenger cushion heater mat C334 pins 1 and 2, component side.
- Is resistance between 0.8 and 1.3 ohms?
Yes
GO to K8.
No
INSTALL a new passenger cushion heater mat. REFER to Seat Cushion Cover - Front Front Seat Cushion Cover. TEST the system for normal operation.
DISCONNECT the battery ground cable. DISCONNECT Restraint System Diagnostic Service Tool from driver seat side air bag module C337. CONNECT driver seat side air bag module C337. REPOWER the SRS. REFER to Air Bag Systems.
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K8 CHECK THE BACKREST HEATER MAT FOR AN OPEN
- Disconnect: Passenger Backrest Heater Mat C335.
- Measure resistance between passenger backrest heater mat C335 pins 1 and 2, component side.
- Is resistance between 0.8 and 1.3 ohms?
Yes
REPAIR seat harness. TEST the system for normal operation.
DISCONNECT the battery ground cable. DISCONNECT the Restraint System Diagnostic Service Tool from passenger seat side air bag module C337. CONNECT passenger seat side air bag module C337. REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new backrest heater mat. REFER to Seat Cushion Cover - Front Front Seat Cushion Cover. TEST the system for normal operation.
DISCONNECT the battery ground cable. DISCONNECT the Restraint System Diagnostic Service Tool from passenger seat side air bag module C337. CONNECT passenger seat side air bag module C337. REPOWER the SRS. REFER to Air Bag Systems.
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