temp gauge has stopped working?

Can you find the temperature sender ? It should be a single wire topped immersible switch lookin thing that threads into the parts near the upper radiator hose and thermostat vicinity on the engine cylinder head. Removing the single wire connector and providing it a ground, then turning the ignition key to the run or on position, should produce a full hot reading on the indicator. Un grounding it should let the indicator fall back below cold. if the indicator responds ? there may be an open in the sender. and a new one can be tried. The senders threads must ground to the metal they screw into, and it should have continuity with the neg batt post, and the body of the vehicle, if not, restore vehicle's grounds