Temperature gauge is not working

"Sender" and "sensor" in this case are two different terms for the same thing. You have two of them because one is for the dash gauge and gives very little trouble, and one is for the engine computer and has caused Ford a lot of running problems. The one for the gauge has only one wire going to it. The one for the computer will always have two wires.

Unplug the wire from the single-wire sensor and ground it. That should make the gauge read full hot when the ignition switch is turned on. If it does, you know the gauge and wire to it are okay. That leaves the sensor. Why there are three sensors listed depends on whether you are looking at three different suppliers or there were three different ones used on your car model. You can buy them from any supplier and any parts store, but Ford is famous for changing something in the middle of a model year. The guys behind the counter at the parts stores will ask you whatever it is about your car that is different according to the notes in their parts catalogs. Most commonly with Fords they will ask you the date the car was built. That can be found in the top left or right corner of the sticker, usually found on the back of the driver's door opening.

The engine cannot warm up without a thermostat. The coolant will circulate through way too quickly and will not have time to get warm. You likely do not have a gauge problem. To tell, feel the air temperature coming from the heater. Also, feel the upper radiator hose it should be too hot to hold onto for very long.

I found three different temperature sensors but did not know which engine size to look up. Two of them have two wires and one of them has one wire. I suspect there is a warning light on the dash along with the temperature gauge. That would explain the second wire.

Replace the thermostat first before you go looking for a gauge problem that probably does not even exist. I just got done typing for over an hour for a fellow who asked what can happen when there is no thermostat in the engine. It boils down to increased fuel consumption, low power, greatly increased engine wear, and higher emissions. Many self-tests will not be run by the engine computer so some fault codes will never set to let you know a problem has been detected.

As for engine wear, you are very unlikely to get 50,000 miles from an engine that is not running at the right temperature. Ninety nine percent of engine wear takes place in the few minutes a cold engine is warming up. That is why vehicles that see nothing but highway driving live to see such ridiculously high mileages, like my 1988 Grand Caravan with almost 400,000 miles. When your engine stays too cold it is constantly wearing excessively with every mile you drive.

I should have said, "As for engine wear, you are very unlikely to get 50,000 more miles from an engine that is not running at the right temperature. The thermostat was not out of the engine for all of it has 200,000 miles.

Nothing is going to suddenly fly apart but excessive wear is taking place in the engine. If I can find my other reply I will paste a copy for you. You are not going to do sudden damage in the short-term but as a person who beats the last ounce of life out of everything before I discard it, I pay particular attention to anything that can make them last longer. Thermostats do not fail as often as people think. They often remove them in a misguided attempt at solving a problem.

As for overheating, if that were to happen, the engine computer will turn the radiator fan on. It does not know about the missing thermostat; it just watches the coolant temperature.

Coolant in a wire or its connector comes from leaking through the sensor. That is not real common but it did follow the wire all the way inside the car on a GM product a few years ago and made puddles on the floor. That is because there were no connectors in between like you normally find at the firewall, and thanks to the rubber weather-pack seals in the sensor's connector, the coolant leaking through it had no place to go except to get forced between the wire and its insulation. In your case, replace the leaking sensor and dry off the coolant on the connector pins. Use a little brake parts cleaner or electrical contact cleaner in a spray can to wash it out. Be sure to check for signs of corrosion or residue that could interfere with it making a good contact.

Your temp sensor is located below the t-stat housing and has two wires going to it. Remove the connector by squeezing it and then pulling. Ground the white/red wire. Turn the key on observe temp gauge. If it goes to full hot. Replace temp sender. No movement. Recheck your jumper to ground connection and retest.

Hi
take a test light or a ground wire, unplug the temp sensor. There is two temp sensors the one for the guage only has one wire to it. Unplug this ground the wire out turn key on does the guage go all the way over? If yes sensor is the prob.

You have to be sure you are working with the right sensor. Write back if this don, t help.