Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. 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 low coolant level. The coolant level switch is mounted at the lowest point in the cooling system surge tank. If the amount engine of coolant in the surge tank drops below the level of the switch, the coolant level switch opens. The coolant level switch signal circuit is monitored by the heating, ventilation, and air conditioning (HVAC) control module. If the HVAC control module detects an open circuit, or a high voltage condition on the signal circuit for greater than 10 seconds, a Class 2 message is sent to the instrument panel cluster (IPC), requesting display of the low coolant level message.