Circuit/System Description
WARNING: This page is about a different car, the 2008 Pontiac G8. However, it is still accessible from the selected car via links, so may be relevant.
The traction control system (TCS) switch is a normally open switch that closes when the switch is activated. When activated, the switch grounds the TCS signal circuit. The body control module (BCM) converts the signal into serial data, which is used by the electronic brake control module (EBCM) to enable/disable the TCS.