Outside temperature gauge ? 2018 Tacoma

Out of no where the display on dash is not reading the outside temp. After truck sits for awhile then starting it it appears but after a few minutes it doesn’t read, just 2 dash lines. Is it Something I should be concerned with as far as Truck? The AC and heat both work

 

On my 2021 OR the sensor is located just in front of the radiator on the center vertical support. Check that out, I do not believe it has anything to do with the function of the truck, only a user goody.

 

The sensor is used in auto mode for the air conditioning system.

Here's some documentation to get you going. It's for the automatic (dual zone) system. If you need the manual (single zone) then let me know and I can provide that data instead.

 

So what you’re saying is I really can’t ignore this and I need to get it addressed

 

If you don't use the air conditioner in auto mode, it's not necessary.

But the fact that it's intermittent makes me think it's something like a loose connection.

 

What do you mean by auto mode? Odd today it is working however it is saying -35° when it’s +30 in my area LOL
Appreciate your help also

 

When the auto button is pressed for the air conditioner. It will adjust the blower speed accordingly.

The temperature is based on resistance between two different metals, if I remember correctly. It's not surprising that it's reading incorrectly, especially if it's just a loose connection.

 

I'm confused. He said outside temperature reading not the cabin temperature sensor.

 

This is GREAT information. Correct too! Much appreciated for more complete documentation. Much better than just seeing a schematic. Is there a "Theory of Operation" statement somewhere on TIS? I assume that is where you got the info. Did you spend a day or two downloading from TIS or do you have a full-time subscription?

My thought that the ambient sensor in front of the radiator was only for the dash display came from when I positioned an aftermarket transmission cooler in front of it and I saw the outside air temp way higher than I was feeling through an open window. Everything else worked properly as far as I could tell.

 

He did. But read my "B1412-12.pdf" attachment in Post #3. There's an ambient temperature sensor (outside) and a room temperature sensor (inside).

 

There's very little documentation (back when I downloaded this in 2017).
I spent a few days in TIS, yes, lol.

 

Yes, but I thought he was talking about the outside temp reading in the instrument cluster center at the very top.

 

Correct. That sensor is also used to control "auto" mode for the air conditioner.

 

Ok I understand. Thank you for the clarification.

 

In the file B1412-12 supplied by ktbell444 it has the following statement "As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases." So an open or high resistance would show lower than the real temperature. Also on that same file which I find strange is the minimal range of the sensor "Ambient temperature sensor / Min: -23.30°C (-9.94°F) Max: 65.95°C (150.71°F)".

For starters find the sensor and unplug it and re-plug it back in. Agree with ktbell444 of a possible loose (or dirty) connector. Finding it is not so easy, mine is bundled with a wire harness and pointing down. Look at the passenger side of the vertical support in front of the radiator and find the two plastic clips positioned in the holes, the sensor is the bottom one. Best access would be to remove the grill if your hands cannot fit. Grill comes off with two 10MM Hex bolts and two press pins next to each headlight, also there is (depending upon how your vehicle is equipped) another wiring harness for the radar. Remove all and pry the whole grill forward from the top. Very simple once you've done it once.

Edit:
Toyota should have positioned this sensor in the up/vertical position to minimize water intrusion with a degraded connector.

 

On page six of the schematic supplied by ktbell444 shows both an Ambient and Cabin temp sensors.

 

Is this the sensor I’m looking for?

 

No, look lower. The sensor will have wires entering from only one direction. Your picture shows a connector.

To clarify further: The sensor is located on the driver's side of the support. It is best IDed by the lower of the two clips protruding from the passenger side of the support.

 

Do u think I can see it from the top of the engine on this 2018? As I don’t see anything below the picture I posted

 

Ha is this it?