Normal Operation
Climate controlled seats are independently controlled by the Dual Climate Controlled Seat Module (DCSM) mounted to the bottom of the passenger seat cushion. The climate controlled seat system only operates with the engine running, however, if using a scan tool to command the DCSM, diagnostic testing can be carried out with the ignition ON. The system receives voltage from Battery Junction Box (BJB) fuse 22 (30A) supplying voltage into DCSM C3265a pins E and F, circuit CBX01 (GN/RD). If voltage is disconnected from either pin E or F of DCSM C3265a both seats will remain operational because the voltage supply circuits are connected internally in the DCSM. However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat will be disabled by the DCSM.
The seat cushion and backrest are equipped with a TED assembly that includes a seat blower (fan motor, serviced as an assembly with the TED). Cabin air is drawn through the blower and distributed to each of the TED modules. The TEDs then heat or cool the air. The air is then directed into the foam pad and manifold where it is distributed along the surface of the cushion and backrest of the seat. Once the system is activated, the DCSM uses a set of flexible algorithms to control the heating/cooling modes and the blower speed dependant on the HVAC module seat switch settings.
- DTC B1113 (Passenger Thermo-Electric Device Control Overtemperature Fault) - If the DCSM TED driver integrated circuit temperature exceeds 175°C (347°F), the DCSM will shut down the passenger seat system and set this DTC.
- DTC B111B (Passenger Thermo-Electric Driver Overcurrent Low) - If DCSM outputs to the passenger seat backrest or cushion TED (circuit pins A, B, C or D at the DCSM connector) or any components within these circuit loops are shorted to ground or a TED resistance of less than 0.9 ohms is sensed, the DCSM will shut down the passenger seat system and set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- TED assembly
- DCSM