New Holland 16115 – ATC: Evaporator Temperature Sensor Open or Short

The Automatic Temperature Control (ATC) module has detected an electrical anomaly in the evaporator temperature sensor circuit, indicating either an open circuit (broken wire) or a short to power. This sensor is a negative temperature coefficient (NTC) thermistor that monitors the evaporator core temperature to prevent it from freezing. An open circuit or short to power causes an out-of-range voltage reading, which compromises the system's ability to regulate temperature and can lead to a frozen evaporator, blocked airflow, and potential damage to the A/C system.

• T6.120
• T6.125
• T6.140
• T6.145
• T6.155
• T6.160
• T6.165
• T6.175
• T6.180
• T7.165
• T7.170
• T7.175
• T7.185
• T7.190
• T7.200
• T7.210
• T7.220
• T7.225
• T7.230
• T7.235
• T7.245
• T7.250
• T7.260
• T7.270
• T7.290
• T7.315
• T8.275
• T8.300
• T8.330
• T8.360
• T8.390
• T8.420
• T8.435
• TG210
• TG230
• TG255
• TG285

1. 1

   Visually inspect the wiring harness leading to the evaporator temperature sensor for chafing, cuts, or corrosion on the connectors.

2. 2

   Ensure the sensor's electrical connector is clean and securely fastened to both the sensor and the main wiring harness.

3. 3

   Verify battery voltage is stable (above 12.1V at rest) and check main chassis and cab grounds for clean, tight connections, as voltage fluctuations can trigger sensor faults.

4. 4

   Disconnect the sensor and measure its resistance with a multimeter. Expected values are roughly 32 kOhms at 0°C (32°F), 12 kOhms at 20°C (68°F), or ~3 kOhms at normal ambient temperature. Infinite resistance indicates an open circuit; near zero ohms indicates an internal short.

5. 5

   Check for continuity on the signal wire between the ATC controller and the sensor connector. Test for a short to power by measuring for voltage on the signal wire with the sensor disconnected.

1. 1

   Discharge AC system

   Have a qualified technician safely discharge the air conditioning system using specialized recovery equipment before opening any part of the HVAC unit.

2. 2

   Access the HVAC unit

   Remove necessary cab components, which typically include side consoles, dashboard panels, and potentially the operator's seat, to access the main air handling unit under the cab floor or behind the seat.

3. 3

   Remove the faulty sensor

   Locate the evaporator temperature sensor probe inserted into the fins of the evaporator core. Pull the sensor out from the core and disconnect its wiring from the main harness.

4. 4

   Install the new sensor

   Carefully insert the new sensor probe into the exact same position in the evaporator core fins to ensure accurate readings. Connect the new sensor to the wiring harness.

5. 5

   Reassemble and recharge

   Reassemble all removed cab components. Evacuate the AC system (deep vacuum) and recharge with the correct amount of R134a refrigerant and PAG 100 oil.

6. 6

   Clear Fault Codes

   After the repair is complete, use a diagnostic tool or the tractor's onboard system to clear the stored fault codes.

7. 7

   Verify Operation

   Start the tractor and run the air conditioning system to verify that it is cooling correctly and that the fault code does not reappear.