Pinpoint Test A: The Heated Seats Are Inoperative
Seats
Pinpoint Tests
Pinpoint Test A: The Heated Seats are Inoperative
Refer to Wiring Diagrams Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
Each front seat uses a heated seat relay located inside the relay connector mounted to the seat track. The relay is accessible by opening the connector housing cover. There are 2 voltage supplies to the heated seat relay. When the ignition switch is ON, voltage is supplied from the Smart Junction Box (SJB) to each heated seat relay coil through heated seat relay enable circuit CHS25 (YE). When the engine is running and the driver or passenger heated seat button is pressed to on, ground is supplied to the opposite side of the driver or passenger relay coil by HVAC module driver heated seat relay drive circuit CHS29 (WH/BU) or passenger heated seat relay drive circuit CHS30 (GY/YE) to energize the relay(s). The switch indicators can only be illuminated with the engine running. The relay contact closes to supply battery voltage from SJB circuit CHS02 (YE/BU) to the driver heater mat circuit CHS11 (VT/GN) or passenger heater mat circuit CHS07 (GY/BU). The driver heater mats are connected to ground circuit GD906 (BK/GY) and the passenger heater mats are connected to ground circuit GD905 (BK/GN) completing the electrical circuits to heat the seats.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- HVAC module
PINPOINT TEST A: THE HEATED SEATS ARE INOPERATIVE
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A1 CHECK OPERATION OF THE HEATED SEAT INDICATORS
- Start the engine.
- Verify the HVAC module operates by checking other climate control system features.
- Press both heated seat switches to on.
- Does the HVAC module operate and do both heated seat switch indicators illuminate?
Yes
GO to A2.
No
REFER to Heating and Air Conditioning to diagnose any climate control system concerns. Otherwise, INSTALL a new HVAC module. TEST the system for normal operation.
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A2 CHECK THE HVAC MODULE FOR HEATED SEAT DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
- Are any DTCs retrieved?
Yes
REFER to the HVAC Module DTC Chart. Diagnostic Trouble Code Descriptions
No
GO to A3.
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A3 CHECK THE HEATED SEAT RELAY CIRCUITS FOR VOLTAGE
- Ignition OFF.
- Depower the Supplemental Restraint System (SRS). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Driver Seat Side Air Bag C367 or Passenger Seat Side Air Bag C337.
- Disconnect: Driver Safety Belt Buckle and Pretensioner C3201 or Passenger Safety Belt Buckle and Pretensioner C3202.
- Disconnect: Driver Heated Seat Relay C3260 or Passenger Heated Seat Relay C3261.
- 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. Refer to Battery.
- Ignition ON.
- Measure the voltage between:
- driver heated seat relay C3260-3, circuit CHS02 (YE/BU), harness side and ground or passenger heated seat relay C3261-3, circuit CHS02 (YE/BU), harness side and ground.
- driver heated seat relay C3260-2, circuit CHS25 (YE), harness side and ground or passenger heated seat relay C3261-2, circuit CHS25 (YE), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
VERIFY SJB fuses 18 (20A) and 43 (10A) are OK. If OK, REPAIR the circuit(s). If SJB fuse 18 (20A) is not OK, GO to A4 to check the heater circuits. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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A4 CHECK THE HEATER CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Driver Cushion Heater Mat C364 and Passenger Cushion Heater Mat C334.
- Measure the resistance between:
- driver heated seat relay C3260-5, circuit CHS11 (VT/GN), harness side and ground.
- passenger heated seat relay C3261-5, circuit CHS07 (GY/BU), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to A5.
No
REPAIR the circuit(s). TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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A5 CHECK THE HEATER MATS FOR A SHORT TO GROUND
- Disconnect: Driver and Passenger Backrest Heater Mat Electrical Connectors.
- Occupy the seat while carrying out the following measurements.
- To check cushion heater mats, measure the resistance between:
- driver cushion heater mat C364 pin 1, component side and ground.
- driver cushion heater mat C364 pin 2, component side and ground.
- passenger cushion heater mat C334 pin 1, component side and ground.
- passenger cushion heater mat C334 pin 2, component side and ground.
- To check backrest heater mats, measure the resistance between:
- driver backrest heater mat connector pin 1, component side and ground.
- passenger backrest heater mat connector pin 1, component side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
CHECK the heated seat wiring, heater mats and connector pins for damage and REPAIR as needed. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new cushion or backrest heater mat. REFER to Seat Backrest Heater Mat Seat Backrest Heater Mat or Seat Cushion Heater Mat Seat Cushion Heater Mat. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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