Saturn Ion Coolant Light Problemsby Justin Cupler
On the Saturn Ion, as with many other General Motors cars, there is a multifunction coolant light on the dashboard. This light comes on to inform the driver of overheating or low coolant level.
When the coolant temperature sensor notices a higher-than-normal temperature -- between 180 and 210 degrees Fahrenheit -- it turns this light on. Once this light comes on, check the temperature gauge and shut the vehicle down if the needle is near the "H."
This coolant light also comes on for a low coolant level. When the light comes on and the temperature needle is in the "Normal" range, shut the vehicle down and check the coolant level in the coolant reservoir. It should be between the "Min" and "Max" lines. Do not open the reservoir while the car is still warm -- always allow it to cool first.
These switches to fail on occasion, as do all components on an Ion. If none of the aforementioned coolant problems exist, you may have a failed sensor. Have the car evaluated by a professional or perform the diagnostics yourself.