Ford Aerostar 1986-1997 Repair Guide

Intake Air Temperature Sensor



The intake air temperature sensor, mounted in the intake air tube to the airflow meter and throttle body assembly, changes resistance in response to changes in intake air temperature. The resistance will decrease as the air temperature increased, and will increase as the air temperature decrease. The sensor provides a signal to the electronic control module of incoming air temperature. This information is used to adjust the injector pulse width and in turn the air/fuel ratio.


  1. Remove the intake air temperature sensor from the intake tube on the vehicle.
  3. Using a hair dryer with adjustable temperature controls, start on the lowest setting and measure the sensor resistance with a multimeter. Record each reading. Do not place the hair dryer directly in front of the sensor. Make sure there is at least a 12 in. (30cm) gap between the sensor and hair dryer.
  5. After the reading has been recorded, adjust the temperature controls of the hair dryer to increase the heat, and point at the sensor. Continue this through the entire heat range of the hair dryer, recording each reading.
  7. If the sensor is working correctly, as the heat from the hair dryer increased, the resistance recorded from the sensor should have decreased. If the mulit-meter reading did not decrease, or decreased, then stopped decreasing, replace the sensor.


See Figure 1

When the battery cable has been disconnected and reconnected, some abnormal drive symptoms may occur while the powertrain control module relearns its adaptive strategy. The vehicle may need to be driven 10 miles (16 km) or more to relearn the adaptive strategy.

  1. Disconnect the negative battery cable.
  3. Access the intake air temperature sensor on the side of the intake air tube, and unfasten the wire harness attached to the sensor.
  5. Using a suitable wrench, remove the sensor from the intake tube.

To install:
  1. Screw the intake air temperature sensor into the intake tube and secure in place with a suitable wrench.

Click image to see an enlarged view

Fig. Fig. 1: Air intake temperature sensor locations

  1. Attach the wire harness to the temperature sensor.
  3. Connect the negative battery cable.
  5. Road test the vehicle.