Temperature Regulation

The position of the heated seat switch determines the regulated temperature of the seats. If the switch is in the LOW position, a 200 ohm resistor is in series with the heated seat relay module's LOW/HIGH input at terminal B. When the switch is in the HIGH position, a 310 ohm resistor is in series with the LOW/HIGH input terminal B. The heated seat relay module differentiates the switch positions by monitoring the voltage drop across the switch.

To regulate the temperature of the seats, a temperature sensor is installed in the seat cushion. The sensor is a variable resistor (its resistance changes as the temperature of the seat cushion changes). The heated seat relay module monitors the sensor resistance through CKT 952 (YEL/BLK) at the sensor input terminal E. When the heated seat switch is in the LOW position and the heating element temperature reaches 37°C (98.6°F), the module opens its contacts removing battery positive voltage (B+) from the heating elements.

If the heated seat switch is In the HIGH position, battery positive voltage (B+) is removed when the heating elements temperature reaches 44°C (111.2°F). The heated seat relay module will cycle on and Off to maintain the desired temperature. The system will remain active until the system or the ignition switch is turned off.