cluster temp gauge problem

[zimzim]

my temp gauge on my cluster goes all the way to the H before i even start the car.
and when i start the car it stays at the H too. ive replaced the thermostat and when the car runs it doesnt seem to overheat. my question is, which one of these temp sensors do i need to replace to fix this ? ive replaced the circled blue sensor and it still does the same thing. do i need to switch the other two out as well >

 

[RonJ]

The red circled sending unit controls the dash temp gauge. The problem could be a bad sending unit, a contaminated connector, or a shorted wire. If you unplug the sending unit, does the gauge needle stay reading cold when the key is turned to ON(II)?

 

[yellowbone12]

had the same problem i changed the one in red and it was good to go