Where exactly is the coolant temp sensor on my 4.0 ohv v6?

It appears to be in the thermostat housing. There are two electrical connectors in the housing. It will be the one closest to the little coolant hose. Sender Unit — Water Temperature Indicator, 4.0L SOHC Removal and Installation 1)Disconnect the battery ground cable (14301). For additional information, refer to Section 414-01. 2)Partially drain the cooling system. For additional information, refer to Cooling System Draining, Filling and Bleeding in this section. 3)Remove the upper intake manifold; refer to Section 303-01B. 4)Disconnect the electrical connector. 5)Remove the water temperature indicator sending unit. 6)To install, reverse the removal procedure.