What is it?

While I’m not 100% certain, I believe the IAT Sensor and the Coolant Temps Sensor are used for engine management.

I am pretty confident, that the sensor in your picture is for outside air temperature readings.

 

Thanks x2 !! I had a early 2000's Buick that used the outside air temp sensor for the fuel injection/engine mgmt, climate control and the outside temp gauge. It also worked with the solar sensor on the dash. I had some hope the this one might have multiple tasks as well. I'll be checking the wire harness behind the the upper console and will report back on the wiring colors. I recall that it was a 14 (?) pin plug with only a couple of wires connected.

 

I did a bit more research. Still don’t have a definitive answer.
But, it does look like the AC System uses the sensor as well.
What I can not confirm is, whether it also will serve as the Outside Air Temp in the 2013+ trucks.

Most of my info is from this link
https://www.tacomaworld.com/threads...sor-install-in-2014-off-road-pictures.307677/

 

More info than I ever expected from a "just for fun" post. I really appreciate it. "Nerd science" I know: Can't help it. Ha!

 

Me too. I like to know what things are and how they work. I understand completely

 

I'm now holding out hope that maybe the truck did have a factory installed auto-dim mirror at some point in time, maybe with the outside temp feature, and it was removed and installed in another vehicle. I can do without the compass, but I sure do miss the outside temp display: especially the one I had that would pop-up a black ice "freeze warning" on the display at certain temp ranges.

 

The first one is the Ambient Air Temperature Sensor, it is used only by the A/C Amplifier which sends a temp signal for the factory mirror that came in the earlier models.
It can not be used for an aftermarket mirror with temperature although I suppose if you could find a factory mirror that had it it would be plug and play.
I put a compass/temp mirror in mine from Bob's Mirrors, he sells a rearview mirror kit that plugs into the factory connector but you still have to run a separate temp sensor which isn't a big deal.


The second picture is the fuel pump resistor that runs the fuel pump at low speed during idle and low engine load.

 

We have our answer @Williston

Thanks Dm93

 

Perfect! Thanks Dm93! It would be interesting to find out what years will share the factory sensor signal. I'm betting the temp sensor behind the grill sends the temp info to the a/c to let it know when it's below 40° to keep the compressor from activating.

I'll work on that: fun stuff!

 

After looking at diagrams on multiple years it appears the mirror wiring from the A/C Amplifier started in 2012 and remained unchanged through 2015 with the exception of the backup camera moving from the mirror to the radio and Toyota dropping the compass/temp mirror in 2014 and 15 year models. Prior to 2012 the compass/temp was a separate display in place of one of the sunglass holders still fed a temp signal from the A/C Amplifier. I'm not sure how easy it would be to come by a 2012-13 mirror, if it would work for sure, or the cost vs buying a Gentex mirror and running a separate sensor.

 

Makes sense. Suspect maybe the shared signal config may have gone away when the temp reading moved from the overhead console to the mirror. Mixed in there as well is the swap of the back-up cam display from the mirror to the audio display screen. I actually think the 2014 brochure may be inaccurate indicating the auto-dim, compass/temp display mirror was included in SR5 trim package.

 

Yes the brochure is indeed incorrect, the TRD Sport/Offroad models were supposed to have it too but didn't.
I read where a few people got dealers to install it for free when they bought their trucks after complaining about it being on the brochure but not equipped on the truck but I'm sure those cases were rare.
That's why I went with the Gentex mirror on mine, I didn't feel like tracking down a 12-13 mirror and hoping it would work.
If I get time and think about it I can backprobe mine and see what kind of signal it is, I can't remember if it's a 0-5v linear analog signal or digital square wave signal.

 

Another mystery answered: thanks again. Lots of questions answered tonight...for me anyway!

 

Well I was going to check the signal on that wire for the temp for you but that wire isn't populated on mine even at the A/C Amplifier so odds are it's not on yours either, my mirror plug only has 3 wires (Ignition Power, Battery Power, and Ground).

 

Thanks guy, I appreciate the info and the time you put in looking into this. Not sure what/who the sensor in front of the radiator is reporting to but I'm sure the mirror plug on mine is the same as yours. Can't whine about something I never had: the fun is in the chase! I'll save my $$ and go with Bob/Gentec when I'm ready.

One question: are the Gentec mirrors compatible with the Totota mounting plate on the windshield? Tnx again.

 

No problem I'm always curious of how things work anyway, makes them easier to diagnose when they don't work
The sensor is connected to the A/C Amplifier only (The A/C Amplifier is not on the data bus so no other modules can "see" that sensor), I'm not sure what it's used for on trucks without an outside temp display maybe it disables the A/C compressor when its below a certain temp? There's no information on it's function, only wiring diagrams and resistance specs.

Yes it should be as long as you have the standard U shaped mounting pad with the single set screw, works great in mine (1-2 hrs install time).

 

I posted a few pics of my install in the thread below.
https://www.tacomaworld.com/threads/accessing-the-ambient-air-sensor-2015.730878/

 

Re: "What is it?" I think I know what this is, but wanted to share it because it makes me smile a bit every time I spot it. Reduction of 7 lbs!!?? Oh no! Looks my days of heavy towing are over! (I put the little piece of foam there to cover the VIN and barcode.)

 

Most likely from a dealer installed add-on, my truck has a similar sticker because it has dealer installed tube steps.

 

i had that sticker as well. wonder what is the reasoning for the dealer putting that on threre.