Seat Temperature Element: Description and Operation

HEATED SEAT SYSTEM
Vehicles with the heated seat option can be visually identified by the two heated seat switches located in the center stack of the instrument panel. The heated seat system allows the driver and front seat passenger to select from two different levels of electrical seat heating (HI/LO). The heated seat system for this vehicle includes the following major components, which are described in further detail later :
- Heated Seat Elements - Four heated seat elements are used per vehicle. Two heated seat elements are integral to each seat, one in the seat back and the other in the seat cushion.
- Heated Seat Module - One heated seat module is used per vehicle. The Heated Seat Module is mounted behind the right rear D-pillar trim panel. This module contains the control logic and software for the front heated seat system. The module also communicates on the CAN data bus network.
- Heated Seat Switches - Two heated seat switches are used per vehicle, one for each heated seat. Both switches are mounted in the instrument panel center stack.
- Instrument Cluster (CCN) - A Cab Compartment Node (CCN) is part of the instrument cluster on this vehicle. The CCN utilizes integrated software and information carried on the CAN data bus network. The Cab Compartment Node (CCN) serves as the link between the heated seat switches and the heated seat module.

The heated seat system operates on battery current received through a fuse in the Integrated Power Module (IPM). Fused ignition switch output (run-acc) circuits are used, so that the heated seat system will only operate when the ignition switch is in the On or Accessory positions. The heated seat system will turn Off automatically whenever the ignition switch is turned to any position except On or Accessory.

A Heated Seat Module is used to control the heated seat system. The module responds to heated seat switch messages and ignition switch status inputs by controlling the 12v output to the front seat heating elements through integral solid-state relays.

When either of the heated seat switches are depressed a resistance signal is sent to the Cab Compartment Node (CCN) or instrument cluster. The Cab Compartment Node (CCN) then sends a CAN bus message to the heated seat module, signaling the module to energize the heating element for the selected seat. The Cab Compartment Node (CCN) also turns on the HI and LO LED indicators on each of the heated seat switches.

The heated seat module energizes an integral solid-state relay, which supplies battery current to the heating elements. When the pre-programmed duty-cycle has been achieved (approx. 2 hours), the module de-energizes the solid-state relay. The module will continue to cycle the solid-state relay as needed to maintain the temperature set point. No heated seat sensors are used with the heated seat system option.

The module will automatically turn off the heating elements if it detects an OPEN or LOW short in the heating element circuit. See the owner's manual in the vehicle glove box for more information on the features, use and operation of the heated seat system.