Case IH NH1065 – EDC: Lower Solenoid Short Circuit

The Electronic Draft Control (EDC) system has detected a short circuit (either to ground or to a voltage source) in the electrical circuit that controls the lower proportional solenoid valve. This solenoid is responsible for shifting the valve spool to allow hydraulic fluid to return to the tank, which lowers the rear hitch. When this circuit shorts, the controller disables the circuit to prevent damage, resulting in the hitch being unable to lower properly or drifting.

• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 225
• Magnum 245
• Magnum 275
• Magnum 305
• Magnum 335
• MXM120
• MXM175
• MXM190
• MX215
• MX245
• MX275
• MX305
• Puma 130
• Puma 145
• Puma 160
• Puma 165
• Puma 180
• Puma 185
• Puma 195
• Puma 200
• Puma 210
• Puma 225
• Maxxum
• 7200 series
• 9300 series

1. 1

   Visually inspect the wiring harness leading to the EDC hydraulic control valve for chafing, cuts, or heat damage.

2. 2

   Check the solenoid electrical connectors for corrosion, bent pins, or loose connections.

3. 3

   Test the wiring harness for a short to ground by checking for continuity between the signal wire pin and a known good chassis ground (there should be no continuity).

4. 4

   Test the solenoid coil with a multimeter for continuity/resistance; a reading of infinite resistance or a dead short indicates a failed solenoid.

5. 5

   Swap the electrical connectors between the 'raise' and 'lower' solenoids; if the fault changes to NH1066 ('Raise solenoid short circuit'), the solenoid itself is confirmed faulty.

1. 1

   Ensure safety and access valve

   Turn off the tractor and disconnect the battery to prevent electrical hazards. Locate the EDC valve assembly at the rear of the tractor near the three-point hitch mechanism.

2. 2

   Repair wiring harness

   If diagnostic checks revealed a short to ground or damaged wiring, repair or replace the affected harness section. Ensure all connections are clean, secure, and protected from the elements.

3. 3

   Replace lower solenoid

   If the solenoid failed the resistance test or swap test, disconnect its electrical connector and unscrew it from the valve body (prepare for hydraulic fluid leakage). Install the new solenoid, ensuring O-rings/seals are correctly seated, and torque to manufacturer specifications.

4. 4

   Clear codes and test

   Reconnect the battery, turn the tractor on, and clear the fault codes using the diagnostic display or tool. Operate the three-point hitch to verify the lowering function works and the code does not return.