Case IH 518861-02 - BCM – BCM (Body Control Module) or ATC (Automatic Temperature Control) Controller: ATC (Automatic Temperature Control) heater control valve actuator - Data erratic, intermittent, or incorrect

The control module is trying to command the cab heater valve to open or close, but it is not receiving a valid, stable position feedback signal from the actuator. Because the module cannot verify the valve's position, the automatic climate control cannot accurately regulate the cab temperature.

• MAGNUM AFS Connect
• Maxxum series (100, 110, 115, 125, 140, 150)
• Puma series (115 through 180)
• Magnum series (180 through 275, MX200-MX275)
• Steiger/STX 4WD tractors
• Axial-Flow series (2366, 2388, 7230, 8230, 9230)
• WD2303
• Patriot sprayers

1. 1

   Inspect the Connector: Locate the heater control valve actuator in the cab HVAC box. Inspect the electrical connector (typically a 4-pin or 6-pin connector) for corrosion, moisture intrusion, or backed-out pins.

2. 2

   Verify Power and Ground: Use a multimeter to ensure the actuator is receiving proper operating voltage and has a solid ground.

3. 3

   Check the Feedback Circuit: Test the continuity of the signal wire between the actuator harness and the BCM/ATC controller to rule out an open circuit, a short to ground, or a chafed wire causing the erratic FMI 02 signal.

4. 4

   Mechanical Binding: Ensure the mechanical coolant valve itself is not seized. If the valve is stuck due to coolant scale, the electric actuator motor will stall, which can also throw an erratic position signal back to the module.

1. 1

   Prep the Machine

   Turn off the machine and disconnect the battery power.

2. 2

   Locate the Valve

   Access the HVAC box / heater core circuit. Depending on the model, this may require removing the seat, accessing the rear cab trim, or opening the cab roof panel.

3. 3

   Isolate the Coolant

   Clamp off the 5/8" heater hoses leading to and from the valve to prevent engine coolant from draining into the cab.

4. 4

   Disconnect

   Unplug the electrical connector from the heater control valve actuator.

5. 5

   Remove the Assembly

   Loosen the hose clamps, pull the hoses off the valve body, and remove the mounting screws securing the valve/actuator assembly to the HVAC box.

6. 6

   Install the New Part

   Mount the new heater control valve and actuator assembly.

7. 7

   Reassemble

   Push the heater hoses onto the new valve, tighten the hose clamps, and plug in the electrical connector.

8. 8

   Finalize

   Remove the hose clamps, reconnect the battery, and top off the engine coolant if any was lost. Start the machine, clear the fault codes, and test the ATC system to ensure the cab heat modulates correctly.