DTC B1321: A/C Low Side Temperature Sensor: Description

A/C low side temperature sensor (located on A/C low side line, near right rear of engine compartment) is a thermistor that controls signal voltage to Dash Integration Module (DIM). DIM applies voltage on circuit No. 731 (Gray wire) between DIM and A/C low side temperature sensor.

When sensor is cold, resistance is high and DIM will sense a high signal voltage at terminal A7 (Gray wire). When sensor warms, resistance is reduced and signal voltage is pulled low through circuit No. 470 (Black wire). Signal voltage varies from 5 volts (open circuit) to zero volts (short circuit). DTC will set when ignition switch is in ON position and sensor circuit is open or shorted.

When DTC is set, A/C compressor clutch will not operate, DIC will display SERVICE A/C SYSTEM and a default temperature reading of 43°F (6°C) will be used.