Case IH 14910:

Check the cab fuse panel for any blown fuses related to the HVAC system, cab power, or the ATC circuit.

Use a multimeter to verify that the ATC module is receiving proper 12V power and a solid ground. If power is missing, the module cannot boot up to communicate.

Inspect the wiring harness connecting the ATC module to the main cab harness (e.g., connectors X397 and X398 on combines). Look for backed-out pins, corrosion, or physical damage.

Check the CAN High and CAN Low communication lines at the ATC connector for continuity back to the ADIC/Armrest controller.

Disconnect power

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

Access the module

Locate the ATC module. Depending on the machine (tractor vs. combine), it is typically mounted in the cab roof/headliner near the blower assembly or inside the side control console.

Remove the faulty module

Disconnect the electrical harness plugs from the ATC module. Remove the mounting screws/hardware and extract the module.

Install the new module

Mount the replacement ATC module (dimensions are approx. 181.4 mm x 123.4 mm x 39.8 mm) and secure the hardware.

Reconnect wiring

Plug the electrical connectors back into the module, ensuring the locking tabs click into place.

Restore power

Reconnect the battery.

Clear codes

Turn the ignition key to the ON position. Access the H8 menu (or use the electronic service tool) to clear stored error codes and reset EEPROM values.

Test operation

Test the HVAC system by adjusting the temperature control knob into the solid blue or red bands to verify that the ATC system is communicating, regulating the heater valve, and engaging the A/C compressor.