Case IH 1071-05 - VCM – VCM: Fan control solenoid current low

Indicates an open circuit or a lack of electrical current flowing through the engine cooling fan's control solenoid. The controller is trying to send a PWM signal to the solenoid to regulate the fan speed, but it is not detecting the expected return current. This usually means the solenoid is unplugged, the wiring harness is broken, or the internal coil of the solenoid has failed (open circuit). The fan will typically default to running at 100% maximum speed continuously.

• MAGNUM AFS Connect
• Case IH Steiger Series (e.g., 500, 600)
• Case IH Quadtrac Series
• Case IH Magnum Series (e.g., 235, 340)

1. 1

   Check the wiring harness connection to ensure it is firmly plugged into the fan control solenoid or Vistronic fan clutch hub (a disconnected plug is the most common cause).

2. 2

   Visually inspect the fan control solenoid wiring for breaks or damage. On Steiger models, check the hydraulic fan drive pump on the right-hand side of the engine above the starter. On Magnum models, check the wiring leading directly to the Vistronic fan clutch hub.

3. 3

   For hydraulic fan drives (Steiger/Quadtrac), verify that the retaining nut holding the electromagnetic coil to the solenoid stem has not vibrated loose or fallen off.

4. 4

   Disconnect the harness and use a multimeter to measure the resistance (Ohms) across the solenoid coil pins. An 'OL' (Open Loop) or infinite reading confirms the internal coil has broken and the solenoid/clutch must be replaced.

5. 5

   Check the harness side for 12V power and a good ground when the tractor is keyed on and commanding the fan.

1. 1

   Power down system

   For Hydraulic Fan Drive Systems (e.g., Steiger): Turn off the battery disconnect switch to ensure the system is powered down.

2. 2

   Locate solenoid

   Locate the fan control solenoid on the hydraulic fan drive pump.

3. 3

   Disconnect harness

   Disconnect the electrical harness from the solenoid.

4. 4

   Remove retaining nut

   Remove the retaining nut at the end of the solenoid stem.

5. 5

   Remove faulty coil

   Slide the faulty electromagnetic coil off the valve cartridge stem. (You usually do not need to open the hydraulic system to replace just the coil).

6. 6

   Install new coil

   Slide the new coil onto the stem, install and tighten the retaining nut, and reconnect the wiring harness.

7. 7

   Verify repair

   Restore battery power, start the tractor, and verify the fan cycles down from 100% speed once the engine is running and cool.

8. 8

   Determine replacement need

   For Vistronic Fan Clutch Systems (e.g., Magnum): If the wiring harness is intact but the internal solenoid of the Vistronic clutch has failed open, the entire fan clutch assembly must generally be replaced.

9. 9

   Remove belt tension

   Remove the serpentine belt tension to free the fan pulley.

10. 10

    Unbolt fan blade assembly

    Unbolt the fan blade assembly from the Vistronic clutch hub.

11. 11

    Unbolt clutch hub

    Unbolt the clutch hub from the water pump/engine mount and disconnect the electrical pigtail.

12. 12

    Install new clutch

    Install the new Vistronic clutch, reattach the fan blades, route the wiring harness safely away from moving parts, and reinstall the drive belt.