Outside temp always shows -40 why? - Acu-Rite AcuRite 00592A2 Wireless Humidity and Temperature Meter

Check or just replace the coolant temp sensor. This sensor will also tell the computer -40 and stop the a/c if bad connection or faulty part.

you are overheating. Check temp sender in block. Also make sure fan relay is operational in fuse box. Fans should come on after about 5 minutes of idle.

Hard to say.
Under normal conditions, vent temp should be about 20 or 25 degrees less than outside air temp.
So if outside air temp is 90 degrees and the engine is at idle speed, vent temp would be around 65 or 70. On the road the vent temp could be less than 60 degrees.
If outside air temp is 70 degrees vent temp will be around 40 - 50.

I would suspect the outise air temp sensor is defective, replace it. It is located in front of the AC condensor core.

Remember it is always colder at the floor level, the heater is pretty close to temp when it is above 40 degrees outside, but as the temperature gets colder outside so does the temperature at the floor level in your house because heat rises.

I use my house furnace thermostat mounted half way up the wall as a guide, When the temp outside is in the teens, I have seen as much difference between the floor temp on the heater and the wall to be 4-6 degrees different. So this means as the tempurature outside drops you need to regulate the thermostat on the heater downward to compensate for the colder floor temperatures.

Ambient air temp sensor could be the cause. Normally located in front grille area.

That is why the A/C clutch is not coming on.If the temp is below 50 degrees the auto control will not allow the compressor to kick in to protect the compressor.You have to check the codes for the body control module.It should show a code for the outside temp sensor.You could have a bad sensor or wiring.If you disconnect it it should show -40 degrees.check wiring and connections.Hope this helps.Good luck.

If there is nothing else wrong with the system you just need to drive it over 25mph for more than 2 minutes. If you slow down below 25mph then you will have to start over. I would recomend getting on the freeway. Don't go over 60mph though, that will make it reset also. If it still says -40 after you are sure you have met the time and speed criteria. Then there is still a problem in the system. Make sure the connector at the temp sensor is clean and the terminals are good.

when its at -40 usually its because the ambient temp sensor is not sending the proper signal to the controller.. it may just be disconnected.. the sensor it behind the grille.. it has a 2 wire connector to it ... itf its connected it may havea broken wire from body damage in an accident... its rare that the sensor fails..

I have a '99 Mercury Cougar & I've been read somewhere that the snowflakes have to do with the outside temp. & traction. I think it's warning you that it may be slippery or icy. I've noticed that when it's +3 to about -2 or -3, the yellow snowflake shows up. Any anything colder than -3 shows the red snowflake. The other lights: the wrench comes up in yellow. That one has always turned on after a certain amount of km's & it's advising you that your car needs a check-up (that's when I know I should look into getting an oil change). You can turn this light off by holding down the two buttons above & below the 'clock' button. Hold them down together for at least 5 seconds & that wrench light should go off. Otherwise, there is a light for checking your breaks (upside down exclamation mark), low windshield fluid. I can't think of any other ones but I hope this helps.