Temperature Sending Unit - how to determine if it's the sensor or a wiring issue?

[Webslinger]

1996 Exp here w/ a temperature gauge that has not worked in years. Just getting in the mood to try and fix some things myself and thought I would start with this.
The temp gauge is dead. By that I mean it never moves, never fluctuates at all.
I understand there are two temperature sending units, but only one controls the temp gauge. That unit has only one wire connected to it.
I also understand there are two common reasons for a non-functioning temp. gauge, 1) bad sending unit, or 2) bad wiring.
I've read some posts that talk about testing the wire that connects to the sending unit by grounding the wire and seeing if the temp. gauge goes to high. If not, then it is likely a wiring issue.
Now, being the noob that I am and having virtually no knowledge about electrical handy-work, I would like to test the wire to see if it is good. So how does one go about "grounding" the wire?
If someone could walk me through that process step-by-step and let me know what tools/items I need to do this, that would be great.
Thank you!

 

[bobflood]

1996 Exp here w/ a temperature gauge that has not worked in years. Just getting in the mood to try and fix some things myself and thought I would start with this.
The temp gauge is dead. By that I mean it never moves, never fluctuates at all.
I understand there are two temperature sending units, but only one controls the temp gauge. That unit has only one wire connected to it.
I also understand there are two common reasons for a non-functioning temp. gauge, 1) bad sending unit, or 2) bad wiring.
I've read some posts that talk about testing the wire that connects to the sending unit by grounding the wire and seeing if the temp. gauge goes to high. If not, then it is likely a wiring issue.
Now, being the noob that I am and having virtually no knowledge about electrical handy-work, I would like to test the wire to see if it is good. So how does one go about "grounding" the wire?
If someone could walk me through that process step-by-step and let me know what tools/items I need to do this, that would be great.
Thank you!

Grounding the wire is very simple. It is the single wire sensor in the thermostat housing; I THINK the wire is red/white. Pull it off the sensor on the engine, hold the metal end on a bare piece of metal almost anywhere on the engine, and see if the guage move all the way up. If you are unsure you are getting a good ground, take another piece of wire, attach one end to the metal end of the sensor wire, and hold the other end to the negative post on the battery. No tools are needed - except maybe some pliers to release the lock and pull the wire off the sensor. Key will probably have to be "on" - engine will not need to be running. Good luck.

 

[Webslinger]

Grounding the wire is very simple. It is the single wire sensor in the thermostat housing; I THINK the wire is red/white. Pull it off the sensor on the engine, hold the metal end on a bare piece of metal almost anywhere on the engine, and see if the guage move all the way up. If you are unsure you are getting a good ground, take another piece of wire, attach one end to the metal end of the sensor wire, and hold the other end to the negative post on the battery. No tools are needed - except maybe some pliers to release the lock and pull the wire off the sensor. Key will probably have to be "on" - engine will not need to be running. Good luck.

I will give this a try today. Thank you!

 

[Webslinger]

So, I'm having a hard time locating the temperature gauge sending unit on my Exp. Took this pic and want to see if I might have gotten lucky. Would this be it?

http://s1171.photobucket.com/user/Webslinger64/media/1996%20Ford%20Explorer/IMAG0620_zps6c05d08d.jpg.html?sort=3&o=0

 

[koda2000]

that looks like it. it's definitely a sender, but i can't tell from your pic because i have no point of reference. no matter, pull the wire off, stick a scrap piece of wire, with the end stripped bare, up inside the wire boot and ground it to the engine block or battery negative terminal. turn on the key (you don't need to start the engine) and check your temp gauge. if the wire and gauge are good, the gauge should now be on full HIGH. if your oil pressure gauge is the one that goes to full HIGH you got the wrong sender.

i had a problem like this and the problem turned out to be my thermostat was stuck poetically open. i didn't think it was the problem (as i was getting heat) until i also got a CEL telling me that my coolant temp was insufficient to achieve closed loop mode. i changed the thermostat and now the gauge works as it should.