<VV> corsa head temp sender checking

[Michael Kovacs]

 I assume the Cyl head temp sender is made to allow the 12V to go to ground as 
the temp rises.  Does this mean that at no headtempthere is no 12V flowing 
through and as the cyl temp goes up, the gage responds with the increased 
voltage therefore moving the head temp gage?

 Bottom line, engine is out and I want to check the sender. How to do this on 
the bench?  I know the gage is not very accurate, but I should read higher then 
200 at highway cruise, also the darn thing some drops off very quickly. I don't 
trust it.
 MIKE KOVACS