It is the thermonstat that does not work. This is a 2001 chevrolet venture,200,000 miles

How do you know or who told you that the thermostat does not work? Please elaborate!

If the thermostat doesn’t work it should be replaced. A new thermostat is not expensive.

What is your question? There’s not much to go on here.

This is a very interesting post. Furthermore it is not elaborated if it the cooling thermostat or the climate control thermostat! But yes, carrie, we need more information if you want complete strangers telling you how to screw up your car worse.

My concern is this. My thermonstat guage stop working. Then service engine soon light came on and stayed. The van does not run hot.