Pinpoint Test N: Both Heated Seats Are Inoperative -- With Heated/Ventilated Seats
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
- Refer to Wiring Diagrams CLIMATE CONTROLLED SEATS
for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Front Seats - System Operation and Component Description .
Possible Sources
- Fuse
- Wiring, terminals or connectors
- HVAC module
- DSM
Visual Inspection and Pre-checks
- Verify the BJB fuse 38 (40A) is OK.
- N1 CHECK FOR DSM (DRIVER FRONT SEAT MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition OFF.
- Ignition ON.
- Using a diagnostic scan tool, perform DSM self-test.
Are any DSM Diagnostic Trouble Codes (DTCs) present?
Yes REFER to the DTC Chart. No GO to N2 - N2 CHECK THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) MODULE HEATED SEAT CONTROL SWITCH PARAMETER IDENTIFICATIONS (PIDS)
- Ignition ON.
- Using a diagnostic scan tool, monitor the Parameter Identifications (PIDs) while pressing and releasing the driver and passenger heated seat control switches.
- Access the HVAC and monitor the CC_SW_D_HSEATSPID
- Access the HVAC and monitor the CC_SW_P_HSEATSPID
Do the Parameter Identifications (PIDs) change when the driver and passenger heated seat control switches are pressed and released?
Yes GO to N3 No INSTALL a new HVAC module. REFER to: Heating, Ventilation and Air Conditioning (HVAC) Control Module . - N3 CHECK THE HEATED SEAT VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- REFER to: Supplemental Restraint System (SRS) Depowering .
- Disconnect: Driver Side Airbag In-line C3051.
- Disconnect: DSM Module C341D.
- Ignition ON.
Are the voltages greater than 11 volts?
Yes GO to N4 No VERIFY BJB fuse 38 (40A) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short. GO to N6 - N4 CHECK THE HEATED SEAT GROUND CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: DSM Module C341A and C341C.
- Measure:
Positive Lead Measurement / Action Negative Lead C341A-9 Ground Positive Lead Measurement / Action Negative Lead C341C-13 Ground C341C-14 Ground
Are the resistances less than 3 ohms?
Yes GO to N5 No REPAIR the circuit in question. GO to N6 - N5 CHECK THE DSM (DRIVER FRONT SEAT MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect all of the DSM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins as necessary
- pushed-out pins - install new pins as necessary
- Reconnect the DSM connectors. Make sure they seat and latch correctly.
- Reconnect all previously disconnected connectors.
- Ignition ON.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new DSM. REFER to: Driver Front Seat Module (DSM) . GO to N6 No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues. GO to N6 - N6 VERIFY THE SRS (SUPPLEMENTAL RESTRAINT SYSTEM) PROVES OUT SUCCESSFULLY
- REFER to: Supplemental Restraint System (SRS) Depowering .
- Connect: Driver Side Airbag In-line C3051.
- Connect all previously disconnected connectors.
- REFER to: Supplemental Restraint System (SRS) Repowering .
Did the SRS prove out successfully?
Yes Repair is complete. RETURN the vehicle to the customer. No REFER to: Airbag Supplemental Restraint System (SRS) .