EVAP Temp Sensor Open

NOTE: After making any repairs, perform BODY VERIFICATION TEST under VERIFICATION TESTS.

Turn the ignition off. Disconnect the ATC C2 harness connector. See Figure. Turn the ignition on. Measure the voltage of the Evaporator Temperature Sensor Signal circuit. If there is any voltage present, repair the Evaporator Temperature Sensor Signal circuit for a short to voltage. With the DRBIII®, reset the ATC after repair/replacement is complete. If there is not any voltage present, go to the next step.
Turn the ignition off. Disconnect the ATC C2 harness connector. See Figure. Measure the resistance between the Evaporator Temperature Sensor Signal circuit and the Blower Motor Control circuit. If the resistance is below 10 k/ohms, repair the Evaporator Temperature Sensor Signal circuit for a short to the Blower Motor Control circuit. With the DRBIII® reset the ATC after repair/replacement is complete. If the resistance is above 10 k/ohms, go to the next step.
Turn the ignition off. Disconnect the ATC C2 harness connector. See Figure. Measure the resistance between the Evaporator Temperature Sensor Signal circuit and the Rear Blower Motor Control circuit. If the resistance is below 10 k/ohms, repair the Evaporator Temperature Sensor Signal circuit for a short to the Rear Blower Motor Control circuit. With the DRBIII®, reset the ATC after repair/replacement is complete. If the resistance is above 10 k/ohms, go to the next step.

Turn the ignition off. Disconnect the ATC C2 harness connector. See Figure. Measure the resistance between the Evaporator Temperature Sensor Signal circuit and the Sensor Ground circuit. See EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT RESISTANCE table. If the resistance is within the specifications, replace the ATC. See A/C-HEATER CONTROL PANEL under REMOVAL & INSTALLATION. With the DRBIII®, reset the ATC after repair/replacement is complete. If the resistance is not within the specifications, go to the next step.

EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT RESISTANCE

Ohms	°F (°C)
5900	100 (38)
6600	95 (35)
7400	90 (32)
8300	85 (29)
9400	80 (27)
10,600	75 (24)
11,900	70 (21)
13,500	65 (18)
15,300	60 (16)
17,500	55 (13)
19,900	50 (10)
22,800	45 (7)
26,100	40 (4)
30,000	35 (2)
34,600	30 (-1)

Turn the ignition off: Disconnect the ATC C2 harness connector. See Figure. Disconnect the in-line C202 harness connector. See Figure. Measure the resistance of the Evaporator Temperature Sensor Signal circuit between the ATC C2 harness connector and the in-line C202 harness connector. If the resistance is below 5 ohms, go to the next step. If the resistance is above 5 ohms, repair the Evaporator Temperature Sensor Signal circuit between the ATC C2 harness connector and the in-line C202 harness connector (HVAC side) for an open. With the DRBIII®, reset the ATC after repair/replacement is complete.
Turn the ignition off. Disconnect the ATC C2 harness connector. See Figure. Disconnect the in-line C202 harness connector. See Figure. Measure the resistance of the Sensor Ground circuit between the ATC C2 harness connector and the in-line C202 harness connector. If the resistance is below 5 ohms, check the wiring harness between the in-line C202 harness connector (plenum side) and the Evap Temp Sensor for an open. Repair as necessary. If OK, replace the Evaporator Temperature Sensor. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in HVAC. With the DRBIII®, reset the ATC after repair/replacement is complete. If the resistance is above 5 ohms, repair the Sensor Ground circuit between the ATC C2 harness connector and the in-line C202 harness connector (HVAC side) for an open. With the DRBIII®, reset the ATC after repair/replacement is complete.