ok guys, i had this same problem on my old '78 corona with a 20R. Basically on both these vehicles, the temp gauge worked, but it didn't go up very far. On my truck it goes up just over the bottom line, and i know it works because on hotter days or sitting in traffic it does go up a little farther than that... any way to make this thing go up to the normal halfway point?
check that the connection is tight and clean. then make sure the wire isnt cracked right at the temp sender on the motor. also remember that toyota gauges are really just a advanced dummy light, not meant to be super accurate, just a general state.
OPEN the radiator cap and start the engine when its cold, if u see fluid moving or going down as u rev it up the thermo is stuck open. could also be ur sender on the intake manifold faulty. or connections or the gauge itself not good.
