Principles of Operation

PRINCIPLES OF OPERATION - HEATED SEATS

Heated Seats
The HVAC module contains the heated seat switches and indicators. The heated seat system functions independently from the climate control system. The system is only operational with the engine running.

Each front seat has a heated seat relay mounted to the seat track. There are 2 voltage supplies to the heated seat relay. Voltage is supplied from the smart junction box (SJB) to each heated seat relay coil when the ignition switch is ON. Ground is supplied to the opposite side of the driver or passenger relay coil by the respective heated seat relay drive circuit output from the HVAC module when a heated seat switch button is pressed to energize the affected relay. This closes the relay contact to supply battery voltage from the SJB to the driver or passenger heater mats. The driver and passenger heater mats are connected to ground, completing the electrical circuit to heat the seats. The cushion and backrest heater mats are wired in series. Both backrest and cushion heater mats contain switch-type thermostats that open and close to regulate the seat temperature. The thermostats regulate and maintain seat temperature until switched off or the ignition switch is OFF.