Theory Of Operation

The switches mounted to the left and right spoke of the steering wheel control both the radio functions and speed control. While the speed control has no ties to the Infotainment system, it is worth mentioning here, since there are shared circuits between the two. The steering wheel switches share power and ground circuits, but have separate LIN circuits to the BCM. These circuits maintain a direct connection with the BCM regardless of steering wheel position via a clockspring in the steering column multifunction switch. On vehicles equipped, the right switch may also contain a temperature sensor for monitoring the steering wheel when the heated steering wheel function is activated. The temperature information is sent to the BCM in the LIN bus message from the right switch. Both switches also share a backlight power feed from the BCM when the park lamps are illuminated. The backlights in the switches are dimmed with the rest of the interior.