Case IH 518861-03 - BCM – BCM / ATC: ATC heater control valve actuator - Voltage above normal, or shorted to high source

The system is detecting a high voltage or short circuit in the heater control valve actuator circuit. Because the actuator is not responding to commands to open or close the valve, the HVAC system cannot regulate the cab temperature, rendering the automatic climate control inoperable.

• MAGNUM AFS Connect
• Magnum series (215, 220, 260, 370, 380 Rowtrac)
• Steiger series (435)
• STX series (375, 530)
• Maxxum series
• 2344 Combine
• 2366 Combine
• 2388 Combine
• FLX3010 Sprayer
• FLX3300B Sprayer
• FLX3510 Sprayer
• Skid Steer Loaders (SR130 through SV340B)
• Compact Track Loaders (TR270 through TV620B)
• Loader Backhoes (580N, 590 Super N)
• Compact Dozers (DL550)
• Forklifts (586H, 588H)

1. 1

   Inspect the 6-pin electrical connector at the actuator (terminals are located at all four corners of the connector) for corrosion, backed-out pins, or moisture

2. 2

   Use a multimeter to test the wiring harness between the ATC controller/BCM and the actuator for shorts to battery voltage

3. 3

   Adjust the cab temperature via the display or overhead controls (between 61°F and 88°F) to verify if the ATC controller is sending proper voltage signals to the actuator

4. 4

   Physically inspect the valve body to see if it is seized, which can cause the electric actuator motor to fail or short out

1. 1

   Locate the Valve

   Access the HVAC box / heater core circuit. Depending on the machine, this is typically located in the overhead headliner or under the cab.

2. 2

   Isolate the Coolant

   Clamp off the 5/8-inch heater hoses leading to the heater control valve to prevent engine coolant from draining into the cab.

3. 3

   Disconnect Electricals

   Unplug the 6-pin molded harness connector from the electric actuator.

4. 4

   Remove the Assembly

   Loosen the hose clamps, detach the heater hoses from the valve body, and unbolt the actuator/valve assembly from its mounting bracket.

5. 5

   Install the New Part

   Mount the new heater control valve assembly (e.g., part 47644646) and reconnect the 5/8-inch heater hoses, securing them with clamps.

6. 6

   Reconnect and Bleed

   Plug in the 6-pin electrical connector. Remove the hose clamps, top off the engine coolant if any was lost, and bleed the cooling system.

7. 7

   Test Operation

   Turn on the machine and adjust the cab temperature controls across the 61°F to 88°F range to ensure the new valve opens and closes automatically.