Actually, the other sensor body is not really a sensor at all but merely used as a ground point. If it has only one wire coming out of it, it's used as ground.

CM

 

if that sensor is loose, then the ground is also loose...hence, the temp gauge will not work...i know this from experience

 

You got that right. But, it's not a sensor- just ground for the ECT sending unit which, is to the right of the ground, has two wires and, is known to induce errors in the gauge at the cluster level. EDIT: I seem to recall there were two and, one was the ETC sensor and one was the sending unit. I will have to use a reference to verify this. I will correct this post if it is not correct.

EDIT No 2: The correct information on this is as follows:

The sending unit for the inside gauge at the cluster (some models) is the one with one wire.

The ECT sensor is the one with two wires and feeds the PCM only.

In order to check them, simply remove the connector shells, flip them upside down and note if the material of the shell/s is not bowed out excessively. This will affect the connection/s and mechanical retention means. Do this for both along with noting the blade terminals in both the ground terminal and the sending unit. If they are green, that's a corrosion issue that needs to either be cleaned or, both should be R&Rd with OEM ones.

CM