ive had issues with the cooling system in my truck(93 3.0 v6) since i bought it...blown hoses, cracked rad, now on a long haul my truck brutally overheated and this was broken. What is it? A hose is supposed to go into it and out. Seems to be connected to the heat inside of the truck. I temporarily connected a socket between the 2 hoses to get me back to the city lol

 

Look at the bottom of page 36, looks like the water valve

http://www.ncttora.com/fsm/1993/airc...g/25heater.pdf

Andy