Coolant Level Control
WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The engine cooling system contains an engine coolant level switch to alert the driver in the event of a coolant loss. When the engine coolant level switch reads a low coolant level in the surge tank, the switch closes. This sends a coolant loss signal to the body control module (BCM) by the low coolant level indicator control circuit. Ground is provided by G101 for the coolant level control.