CTS V6-3.2L VIN N (2003)
Coolant Level Sensor: Description and Operation
Coolant Level Control
The engine cooling system contains an engine coolant level switch to alert the driver in the event of a low coolant level.
When the engine coolant level in the surge tank falls below a certain level, the coolant level switch opens. When the HVAC control module detects an
open, or a high voltage level, on the coolant level indicator control circuit for at least 10 seconds, it will send a class 2 message to the radio requesting
display of the low coolant level message.
There is approximately a 10 second delay before the HVAC control module sends the class 2 message, to prevent the message from being displayed due
to coolant sloshing in the surge tank.