Temperature Regulation

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

When the ignition is turned to the ON position, the heated seats will initialize in the OFF state. With each activation of the heated seat switch, the body control module (BCM) will cycle temperature setting in the following manner: HIGH, LOW, and OFF.

The heated seat system is designed in order to warm the seat cushion and seat back to approximately 42°C (107.6°F) when in the high heat position, and 37°C (98.6°F) when in the low heat position. The BCM monitors the seat temperature through the temperature sensor signal circuit and the temperature sensor (thermistor) that is located in the seat cushion. The temperature sensor is a variable resistor, its resistance changes as the temperature of the seat changes. When the temperature sensor resistance indicates to the BCM that the seat has reached the desired temperature, the module removes battery voltage from the heated seat relay control circuit de-energizing the relay. The relay then opens it's switch contacts removing battery voltage from the heated seat element supply voltage circuit and the seat heating elements. The module will then cycle the relay control circuit on and off in order to maintain the desired temperature.