New Holland ATC 125 – Automatic Temperature Control (ATC) controller: High pressure switch (+) input shorted to power

The system has detected a short to a power source (12V) on the positive side of the air conditioning (A/C) high-pressure switch circuit.

• T6 Series
• T7 Series
• T8 Series
• T9 Series
• TV series (TV140, TV145, TV6070)
• older Versatile/Ford-New Holland models
• CR Series (CR9090, CR9080, etc.)
• CX Series (CX8080, CX8090, etc.)
• FR Series (FR9040, FR9050, FR9090, etc.)
• L200 series
• C200 series

1. 1

   Visually inspect the wiring harness and all electrical connectors between the A/C high-pressure switch and the ATC controller.

2. 2

   Check for chafed wires, melted insulation, or pinched harnesses that could be exposing the switch's signal wire to a 12V power source.

3. 3

   Disconnect the switch to see if the short-to-power code changes to an open circuit code. If the code remains a short to power with the switch unplugged, the short is in the wiring harness or the ATC module itself.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Switch

   Find the A/C high-pressure switch, which is threaded into the high-pressure side of the A/C refrigerant lines.

3. 3

   Harness Repair

   If the diagnostic checks revealed a short to power in the wiring, repair the damaged section of the harness using proper weather-sealed splices, or replace the damaged connector pigtail.

4. 4

   Switch Replacement (if internally shorted)

   Verify if your specific machine has a Schrader valve beneath the switch fitting. If it does not, the A/C system refrigerant must be properly recovered by a certified technician before removal. Unthread the old high-pressure switch from the A/C line. Thread the new OEM replacement switch into the port. Reconnect the electrical plug.

5. 5

   Recharge and Clear

   If the system was evacuated, pull a vacuum and recharge the A/C system to OEM specifications. Reconnect the battery, turn on the machine, and clear the ATC 125 fault code.