Case IH 520557-02 - ACM – ACM: Air conditioning temperature increase switch circuit fault.

The control module is receiving an erratic, intermittent, or incorrect (unstable, illogical, or out-of-range) electrical signal from the switch used by the operator to increase the cab's A/C temperature setpoint.

• MAGNUM AFS Connect
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 215
• Magnum 225
• Magnum 235
• Magnum 240
• Magnum 245
• Magnum 250
• Magnum 260
• Magnum 275
• Magnum 280
• Magnum 290
• Magnum 305
• Magnum 315
• Magnum 335
• Magnum 340
• Magnum 370
• Magnum 380
• MX210
• MX215
• MX245
• MX275
• MX305
• Steiger 280
• Steiger 330
• STX430
• STX480
• STX530
• Maxxum 100
• Maxxum 110
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 135
• Maxxum 140

1. 1

   Verify the Armrest Controller Module (ACM) calibration status on the dealer scorecard to ensure the software is up to date, as updates can correct erratic code logging.

2. 2

   Inspect the A/C temperature increase switch on the armrest console for physical damage, sticking, or liquid intrusion/debris.

3. 3

   Check the wiring harness routing from the A/C control panel to the ACM board for chafing or pinched wires.

4. 4

   Inspect the connectors for loose, backed-out, or broken pins, and perform a pin drag test to ensure proper terminal contact.

5. 5

   Test the switch circuit for continuity and verify if the voltage or resistance changes smoothly and correctly when the temperature increase switch is actuated.

6. 6

   Check the 5-volt reference and ground circuits supplying the armrest control panel, as a loss of reference voltage can cause erratic switch data.

1. 1

   Power down the tractor and disconnect the battery to prevent electrical shorts while working on the armrest electronics.

   Power down the tractor and disconnect the battery to prevent electrical shorts while working on the armrest electronics.

2. 2

   Remove the retaining screws/clips to lift the armrest control console cover, exposing the internal climate control switches and the ACM circuit board.

   Remove the retaining screws/clips to lift the armrest control console cover, exposing the internal climate control switches and the ACM circuit board.

3. 3

   Carefully disconnect the wiring harness connectors from the A/C climate control switch assembly.

   Carefully disconnect the wiring harness connectors from the A/C climate control switch assembly.

4. 4

   If the switch or potentiometer is faulty, remove the mounting hardware holding the climate control console assembly in place.

   If the switch or potentiometer is faulty, remove the mounting hardware holding the climate control console assembly in place.

5. 5

   Install the replacement climate control switch/console assembly into the armrest.

   Install the replacement climate control switch/console assembly into the armrest.

6. 6

   Reconnect the wiring harnesses, ensuring all connectors snap securely into place to prevent future intermittent faults.

   Reconnect the wiring harnesses, ensuring all connectors snap securely into place to prevent future intermittent faults.

7. 7

   Reassemble the armrest console cover.

   Reassemble the armrest console cover.

8. 8

   Reconnect the battery, turn the ignition key to the ON position, and use a diagnostic tool to clear the 520557-02 fault code.

   Reconnect the battery, turn the ignition key to the ON position, and use a diagnostic tool to clear the 520557-02 fault code.

9. 9

   Test the A/C temperature increase and decrease functions to verify the repair.

   Test the A/C temperature increase and decrease functions to verify the repair.