Any way to test it? Pull it out and plug it in and see if the plunger moves?

 

How many miles on your truck?

 

112025 miles

 

You would normally see movement when key is turned, but please resist temptation to move the plunger by exterior means (tweezer, pliers, fingers, etc.). If you replace it, the truck can take a number of drive cycles to learn the new one, or a trip to dealer to reset adaptive values.