which coolant sensor on a 94 jeep grand cherokee 5.2 L would be the one that controls the gauge hand for the temp gauge i see 2 of them one one leg on the left of thermostat housing and a 2 leg one on the right side? for sometime now my temp gauge and heat inside has not got up temperature (warm) usually runs about 150 degrees where it should be 210 degrees no fault codes i have replaced both of the sensors mentioned above also a nes thermastat all today to no avail after replacing all these my hand now wont move from the cold position hand does not move at all evenafter 20 min drive??

This is my experience on my Jeep w/ a 4.0, but hopefully this will help out, but take it with a grain of salt. . .

On the 4.0 the 1-pinned sensor is the sending unit (talks to the insturments) and the 2-wire one runs to the PCM (tells the computer how hot the engine is). There are, evidently, two types of those sending units out there. . . . one that activates an idiot light, and one that goes to a guage. My problem was the first shop I went to sold me item 1 when I needed item 2. You can always check the wiring as well, to make sure there's no short/crack in the wiring; I took a short strand of junk wire and grounded the vehicle side of the clip to the engine block. This should make your guage peg on 'hot' if the wiring is working correctly.

A word on after-market. I don't know if you bought the replacement sending unit from a Jeep dealership or not, but if you buy aftermarket, it's been my experience that some stores selling after-market sensors may not have the second version of that sensor, for the record I purchased mine @ Carquest, but YMMV. (Of course, having said all this, if testing the guage like above does work, you may have also been sold a bum sensor :-D Good luck w/ the fix)

it definitley was the one wire sensor for the gauge the connector was broken from heat i guess wire was not touching the sensor i took the connector off and got a new sensor where the wire plugs in from the engine plastic protector was broken also so i connected it to the sensor and the filled the connector with blue atv sealant that says safe for sensors i hope it is does any one know for sure anyways the hand is now registering correctly..