2010 buick lacrosse Air Conditioning

2blbogey

my lacrosse is indicating the outside air temp is -40f. the ac wont turn on. only the heater. what could be causing this?

kyfdx

A bad temperature sensor?

thecardoc3

-40f is the default temperature for an open ambient temperature sensor circuit. The sensor is on the bumper cover on the left front corner if the car. There is a grill section below the bumper between the fog lights. The sensor is located on the drivers corner of that part of the bumper. With the sensor unplugged, there should be a 5v signal on the dark green/white wire and ground on the yellow. With the sensor connected normal operating voltage will range from about 1.5v to 4v depending on the temperature. (colder = higher voltage)