Temp Guage on 1990 Ranger 2.9 V6 does not work
 

My temperature gauge on my truck has not worked since I purchased it a few weeks ago. I want to locate the sensor, and I believe I have found it, but I wanted to check with you guys first. It appears its located on the thermostat housing? I found this information on the internet for a slightly older Ranger, and thought it might be a good idea to check and sure enough, there is a sensor going into the side of the thermostat housing. Is this the one I'm looking for? Being that I know almost nothing about the truck, I don't like the idea of the temperature gauge not working so I wanted to trouble shoot it. My understanding is that it is a one wire plug, and if I ground that single wire, the gauge will max out at hot provided the gauge is working and this would indicate a bad sensor? If not, the sensor may or may not work, but the gauge is shot? Is my understanding correct?

I guess I was wrong because I found a post elsewhere about it. the 89 ranger had a two wire temp sensor.. I found a diagram of the engine though :)

I found the sensor, its located just above the thermostat housing to the right. The sensor I thought it was to begin with is actually the ECT. Anyway, just an update. Tested it, and the gauge is good, so I'll be replacing the sensor shortly!

Its called a Sender there are two, oil pressure sender and an ECT(engine coolant temp) sender, they are for the dash gauges, they are grounds for 12volt gauges

ECT sensor is for the computer if you have fuel injection, its a 5volt sensor and always has 2 wires, not interchangeable with the 12volt temp sender

If you ask for a temp sender the parts guy will bring you a sensor first time around, so stress SENDER, NOT sensor

A sender can have 1 or 2 wires, pre-2000 they will pretty much all be 1 wire
A sender's threads are used for Ground to engine, so lower threads MUST BE left as bare metal, if you want to add a sealer then do it to upper thread

If you Ground the wire from a sender, oil or temp, the gauge in the dash should go up all the way, assuming key on
That tells you the wire and gauge are OK, sender is bad

In the case of oil pressure sender if its a 1990 and up Ford, gauge will only go up 1/4 or so when you ground it wire, thats OK, wire and gauge are good, replace sender