Principles of Operation - Heated Seats

The driver and passenger heated seat modules share a common battery feed and ground source and have a separate ignition feed. The electronic automatic temperature control (EATC) module includes the heated seat control buttons and indicators. The heated seat system will function when the EATC module is ON or OFF. When a heated seat control button on the EATC module is pressed with the ignition switch in RUN or START, a momentary ground signal is sent to the heated seat module. Upon receiving a signal, the heated seat module will decrease one setting (the sequence is HI, LO, OFF, HI, etc.). When a heated seat is set to HI, both LED indicators above the heated seat control button will illuminate. When a heated seat is set to LO, only the left LED indicator will illuminate. When a heated seat is set to OFF, neither LED will be illuminated. Refer to CLIMATE CONTROL SYSTEM - GENERAL INFORMATION AND DIAGNOSTICS article.

When the heated seat system is ON, the heated seat module then supplies power to the heating element circuit. The cushion element and backrest element are wired in series and powered by the same output. The heated seat module will remain ON until the heated seat control button is pressed to cycle the heated seat module to the OFF state or until the heated seat module automatically shuts off after 10 minutes. If the ignition source is removed from the module, the heated seat module will enter an OFF state and will not return to ON until the heated seat control button is once again pressed with the ignition switch in RUN. The heated seat module is designed to heat the seat to 37.5°C (99.5°F) in LO setting and 42°C (107.6°F) in HI setting and maintain the temperature until switched OFF. This temperature is maintained by the heated seat module monitoring the temperature sensor, located in the seat cushion element, and adjusting the current flow to the heating elements.