New Holland 16132 – ATC: Low Pressure Switch (-) Shorted to Power

The Automatic Temperature Control (ATC) module has detected a short circuit to a power source in the low-pressure side of the A/C system's pressure switch circuit. The low-pressure switch is a safety component that monitors refrigerant pressure on the low-pressure side of the A/C system. Its primary function is to disengage the A/C compressor clutch if the refrigerant pressure drops below a safe operating threshold, preventing damage to the compressor from running without sufficient lubrication. When the ATC controller detects a constant voltage on the negative side of this circuit, it interprets it as a short to power and logs fault 16132.

• T5
• T6
• T7
• T8
• T9
• T6010
• T6020
• T6030
• T6050
• T6070
• T7030
• T7040
• T7050
• T7060
• TM Series
• TS100A
• TS125A
• TS130A

1. 1

   Verify A/C refrigerant level to rule out a genuine lack of refrigerant due to a leak (an open switch from low pressure is a critical first check, though it typically shouldn't cause a short to power fault).

2. 2

   Inspect the wiring harness leading to the A/C low-pressure switch for chafed, pinched, or melted insulation that could allow contact with a power source or another wire carrying voltage.

3. 3

   Check electrical connectors at the low-pressure switch and the ATC controller for corrosion, moisture intrusion, or pushed-out/damaged pins that could create a short circuit.

4. 4

   With the key and A/C turned on, test the voltage at the signal wire of the low-pressure switch to see if unexpected system voltage is present.

5. 5

   Disconnect the switch and ATC controller, then use a multimeter to check for continuity between the signal wire and a known 12V power source wire (there should be no continuity).

6. 6

   Check for continuity to ground on the signal wire to rule out a short to ground. A short to ground would typically present as a different fault code (e.g., 16133), but it is good practice to check.

1. 1

   De-pressurize the A/C System (If Necessary)

   While many pressure switches are installed on Schrader valves that close when the switch is removed, it is best practice to safely recover the refrigerant from the A/C system before opening any part of it. This prevents accidental refrigerant release.

2. 2

   Locate and Disconnect the Switch

   The low-pressure switch is typically located on the low-pressure A/C line or on the receiver/drier. On some T-series tractors, access may be under the operator's seat platform. Disconnect the electrical connector from the switch.

3. 3

   Test the Switch (Optional)

   A normally open low-pressure switch should show no continuity across its terminals when the system pressure is low or zero. It closes to complete the circuit when sufficient pressure is present (e.g., above 20 PSI). If the switch is shorted internally, it may fail this test.

4. 4

   Replace the Low-Pressure Switch

   Unscrew the old switch from its port. Ensure the sealing O-ring or Schrader valve is in good condition. Thread on the new switch and tighten it to the manufacturer's specification, being careful not to over-tighten.

5. 5

   Reconnect and Re-evaluate

   Reconnect the electrical connector.

6. 6

   Evacuate and Recharge the A/C System

   Use a vacuum pump to evacuate the A/C system to remove air and moisture.

7. 7

   Recharge the System

   Recharge the A/C system with the correct type (R134a) and quantity of refrigerant according to the tractor's specifications.

8. 8

   Clear Fault Codes

   Use the tractor's diagnostic menu or a service tool to clear the 16132 fault code.

9. 9

   Verify Operation

   Start the tractor, turn on the A/C, and verify that the compressor engages and the system cools properly. Monitor for the return of any fault codes.