I bought a 1999 Ford Ranger Sport with a long bed, 2wd 2.5L a few weeks ago and have been doing the routine matinence that was not so routine for the PO. I have a chiltons book and have been using FTE and other sited for info but was unable to figure out where the coolant temperature sender was. Most said in the block or intake manifold and that it has only one wire. I eventually found both the sensor for the engine and the sender for the gauge in the thermostat housing. I thought I would post a picture for anyone who cant see what is directly in front of them. It is a little embarrasing since it is really right in plain sight. I replaced the sender and it fixed the problem. I had bought the sensor so i replaced that too, even though the old one was probably fine.