Ok, so I did scour the forums quite a bit looking for this and didn't find a solution that worked for me yet. I have a '15 250 6.2 and appears to be the work truck package. I say this because when I dived into ALLDATA (can access it at work) the only AC system that matched was that. Came with the vinyl flooring and non sync radio so I'm inclined to agree.

Anyway, the dash displays -40 at startup. Been this way since I bought it in April, but at the price point I found this at, couldn't say no. I'm also aware that my truck is missing the original mirrors. I figured the AAT sensor was supposed to be in mirrors and that was the problem, as I don't have it on the grill. One thing I did find in AllData yesterday was a troubleshooting guide that had me press the ac and circulation buttons together and then the ac button within 2 seconds of each other (manual ac) and voila it changes the temp to a more realistic 80ish (this morning at 71 which was accurate) depending on the time of day.

I did find every startup I have to do that to get an accurate reading.

The question I have now is, is this getting the readout from the MAF (which if that's the case could be going bad?) and just simulating the AAT or would adding an AAT harness and sensor back into the mirrors fix it? I have no problem wiring on a vehicle, just looking for any thoughts and if anyone has dealt with something similar.

 

I ran into this issue when I replaced my busted passenger side mirror. I just spliced in the old sensor and stuck it inside the mirror housing. A new sensor is around $13 on ebay.

 

Previous owner was kind enough to leave wire to solder.
I've gone ahead and ordered new mirrors, had same features as original oem mirrors apart from sensor. I've ordered the sensor harness and sensor and will set that up tonight. Any wire/pinouts available for which sensor harness wire goes where?

Where did you locate the sensor in the new mirror?

 

I just stuck the sensor inside the mounting area of the mirror behind the rubber seal. Temp isn't quite as accurate due to being so close to the cab with the heater on, no biggie unless you have automatic climate control. I busted my old mirror apart to retrieve the sensor and wires and just matched the wires up and spliced them.

 

I ended up doing the same last night. For future reference in case anyone ever has this issue, pin 12 and pin 13 which are yellow/green and yellow/violet are the wires you're looking for. It was accurate enough. the mirrors I received work well, found that the horizontal controls are inverted, so left turns them right but I'll fix that later.

That harness is expensive at 25+ unless you go to a salvage yard. I didn't have one so I amazon ordered and was done with it. Thanks for the pointers.