My water temperature gauge quit working suddenly and I am not sure where it is located on my 1980 Toyota 4x4. I believe it is the sensor in the picture below with the green wire.




If so, is there anyway to test the sensor?

Thanks in advance to anyone that can help with this issue

 

what picture?

 

Oh, I can see the picture on the thread on my computer. Not sure what is wrong. I'll try to repost.

 

I uploaded the pic to another site so I hope you can see it now

 

Try hooking the yellow wire to the sensor on the valve cover side of the thermostat housing.

 

Also i think the green wire in the photo goes to the temperature switch for the emissions computer mine is not hooked up at all just the yellow wire and my temp gauge works great.

 

Your temp sensor is the one a the top center of the picture you have posted. It does not have a wire on it. The yellow water temp. sensor wire should be connected to the tab on the sensor.

 

Thanks for your reply. My gauge was working before with the green wire hooked up to the side sensor as shown. It no longer is working. I removed that sensor and checked the resistance. Infinity. So there must be an open in it. I had the hardest time trying to find the right sensor to replace it with. The one I found I installed and inserted the green wire and then the gauge still did not work. Wow, two things gone wrong at once? Hmmm. So for the heck of it, I tried using the yellow wire. It works now. However, the usual warm reading of about 1/4 up the gauge is now 3/4, but at least I have a reference point.

 

Yeah, I do not have the emmisions computer either, but it was my yellow wire that was not hooked up to anything.

 

Thanks for your reply. I believe I tried hooking the yellow wire to that top sensor and did not have any luck. It is possible that that sensor was bad in the past and the previous owner utilized the side sensor.

 

The side sensor with the green wire is for the emissions computer. The top sensor is for your temperature gauge. Both sensors are available from your Toyota dealer. The green wire sensor does not output a proportional signal which is required by your temperature gauge it only makes ground at a set temperature to tell your emissions computer your engine has reached normal operating temperature. If you hook your gauge to the side sensor you will get a false reading of actual engine temperature. DO NOT DO THIS!! Get new sensors and save your engine.

 

Well I have been driving 2 years with the way it was hooked up in the picture. The gauge seemed to be working well, with the reading about 1/4 up the gauge and gave good readings when I would climb extended distances up mountains and it would rise near hot. I am now using the yellow wire, which works as well, but with a higher normal reading of 3/4 up the gauge. Although this will give me some idea that the engine is starting to get hot, it is likely to show Hot before it is actually at the danger point. You are right, I need to get the correct sensor. It has been difficult to find as I believe the engine is a 1980-1984 22R Block with a 20R head which I have no clue what year or vehicle it came from. I suppose the best thing to do is actually go to the Toyota dealer and have them take a look at it so I am assured of getting the right one. Thanks for your input.

 

I have a 22R motor with a 20R head built by LC engineering. I run twin 45DCOE Weber carbs and I replaced my sensors about a year ago. They are still available from Toyota Like I said earlier. The sensor for my electric fan is now in the location where your emission switch is and I moved my emission switch up into my outlet water neck. Go to my album: suncomb1-My Toy and you will find a photo of my motor setup.