My ac controller is reading 27 degrees outside causing the air not to work

The computer enriches the fuel mixture and then leans it out to see fluctuation and changes at the oxygen sensor readings, these changes forth and back can often be noticed, also AC pumps cycle from time to time for short bursts just to keep them freed up i think. when the AC clutch kicks in the idle will also fluctuate, again it is normal to some degree. As for air pockets fill the cooling system there should be no air pockets at all nothing but coolant. Air does a poor job of drawing heat from the engine from the inside of a cooling system however it works well outside the cooling system.

look like the program is not working. if the set temp, is lower than the real temp, heather should come on.
if the set temp is higher than the ambient temp. the ACC should come on.
I will try one first, then setup the other.

sound like faulty out side air temperature sensor located center radiator support.

Hi. Try to check first your refrigerant. One cause of this problem is refrigerant is running low. Did this happened from the time you turn on the AC? or at first AC is cold then after driving for a certain period of time the AC will get warm?

If the outside temp.sensor is reading -38 degrees then this is what is causing the compressor not to come on.You need to check the wiring to the outside temp.sensor and the sensor.Make sure it is connected.It is located on the front grill area.Between the grill and the bumper cover.Hope this helps.Good luck.

could be a problem with the blend door. common on explorers. open glove box all the way down (bend in tabs to where it will open further than normal) . take flashlight and look behind it to top of black box inside dash. should be able to see tab for door moving while changing the temp. on the control unit. if it is broken should be able to hear cracking or popping from inside heater case.

JUST A BIT OF INFO WHEN YOU CALL THE PARTS STORE, THE PART YOU WILL ASK FOR IS CALLED THE AMBIENT CLIMATE CONTROL SENSOR. THEY WILL NEED TO KNOW THAT OR THEY WILL TRY AND SELL YOU A BUNCH OF PARTS YOU DONT NEED.

There are four sensors for ambient tempurature and they work in unison to provide information to the temp reading on the dash, the heater control head ( where to direct air, blending of warm/cold/outside/inside air flapper controls) depending on the ambient temp and the inside air temp sensor located just above the radio as well as the sun sensor on the top of the dash as well as the a/c compressor head.

When you start your car, the body control module takes the readings from all sensors, outside air temp located in front of the radiator, air temp sensor located in the airbox ( senses temp of air being drawn in from the outside into the air box), coolant temp, inside air temp sensor and the sun sensor on top of the dash (this is why it takes a few seconds for the climate control system to begine when you start the car). The intake air sensor is 1st priority, inside air second, coolant third, ambient 4th and sun 5th. For instance, if the sun sensor reads the sun is hot but the interior sensor reads cold, the inside akes priority. The goal is for the system to achieve a tempurature inside the car that matches the selected temp. It uses all of the sensors to set the system up to achieve that goal as quickly as possible.

Example; Its mid afternoon, sunny and 40 degrees outside adn your in stop and go traffic. The intake sensor reads 40 degrees, the outside sensor reads 60 degrees (heat from radiator...engine heat protrudes into cabin) and the sun sensor reads high (sun is strong). The system is set for 72. priority one sensor reads 40, inside sensor reads 65, ambient reads 60= system will blow hot air to the floor out put, dash outlets will lightly flow 65 degree air so the sun doesnt roast you yet your feet are cold(if it blew hot air from all outlets, your upper body would be hot but your legs/feet would be cold). as the interior sensor reaches desired temp, air will be distrubuted through thee dash, defrost and floor with the warmest air coming out the floor and defrost, coolest air out the dash vents. Its a complex system!

The two sensors that will screw the system up the most are the intake and interior sensors. the system will function reasonably well with just those two sensors though it wont blend air temps between outlets if the sun sensor isnt working. If the outside sensor fails, it simply uses the intake sensor, if the intake sensor fails it will rely on the front sensor. However, since the intake takes priority over the outside sensor, if the intake sensor sends incorrect resistance info rather than failing, it will take priority and cause the unit to malfunction such as in your case.

The intake air sensor can be changed from the outside with patience. If it where me, I would pay the two hrs labor and let the dealer do it right.

Kevin,
Kevins Small Engine service,
South Berwick ME. 03908

The ambient air temperature sensor is bad or has a connection/wiring problem. It is not blowing cold air because it thinks the outside air is less then 35degrees. When the computer sees outside air less than 35 it disables AC so that ice will not form inside the vehicle and in HVAC system. The sensor is directly behind the front grill. You might be able to check it for connection/corrosion/frayed or damaged wires. If no evidence of this I would replace it.

disconnect sensor then a/c will read it as default or not read it so ac will work more manual than auto