Modern cars have numerous sensors that send information to the vehicle's control modules. One sensor in particular that sends information to several systems is the ambient air temperature sensor, also known as the outside air temperature sensor. The ambient air temperature sensor information can be used to calculate fuel mixture and can be used to determine air conditioning temperature. This sensor can be found in a number of different places on a car, but fortunately it is not too difficult on a 2002 Nissan Altima.
Kneel in front of the vehicle, and -- using a flashlight -- look inside the lower grill opening towards the drivers side of the car.
Locate the black plastic sensor in the corner of the grill opening. It's easy to identify because it is connected to an orange wire with a black stripe and a black wire with a yellow stripe.
Press the plastic tab on the connector with your finger to release the lock. Pull the connector from the sensor.
Pry the mounting clip away from the bumper with the flat-head screwdriver to release the sensor from the bumper. Do not apply too much pressure to avoid breaking the bumper mount.
Install the new sensor by pressing it onto the mounting tab until the clip locks in place. Install the connector back onto the sensor until it clicks in place.
