Case IH 520570-05 - BCM – BCM (Body Control Module) or Cab Controller: Rear wiper motor - open circuit

The FMI "05" translates to "Current Below Normal or Open Circuit." This means that when the controller attempts to send power to the rear wiper motor, it does not detect the expected electrical current draw. This condition is typically caused by a disconnected electrical plug, a broken wire in the cab harness, a failed rear wiper relay, or an internal break (open circuit) inside the wiper motor itself.

• MAGNUM AFS Connect
• Magnum Series (MX210, MX230, MX255, MX285, 235, 260, 290, 315, 340)
• Steiger / STX Series (STX325, STX375, STX450, STX500)
• Maxxum Series (110, 115, 120, 125, 130, 140)
• Puma & Optum Series
• Farmall / JX / MXU Series

1. 1

   Check Motor Power: Disconnect the electrical connector at the rear wiper motor. Turn the ignition ON and the wiper switch ON. Check for 12 volts at the power supply cavity on the harness side.

2. 2

   Check Motor Ground: Confirm the rear wiper motor ground circuit has good continuity to the chassis ground. If power and ground are both good at the connector, the motor itself has an internal open circuit and must be replaced.

3. 3

   Check Switch Power Supply: If there is no voltage at the motor, check for 12 volts at the rear wiper switch connector. If the power supply to the switch is good but no power leaves it, the switch or universal switch module may be faulty.

4. 4

   Check the Relay: Test the rear wiper relay. Measure the voltage at the open circuit between the 12/24 volt relay and the battery.

5. 5

   Harness Continuity: Measure the resistance of the wiring harness between the BCM/switch and the rear wiper motor to ensure there are no broken wires in the cab roof harness.

1. 1

   Access the Motor

   According to Case IH service manuals, access the rear wiper motor by referring to the "Cab Top Removal and Installation" procedures. Note: The cab top/roof usually does not need to be completely removed; you can often access the motor by loosening the rear of the roof or dropping the rear interior headliner panel.

2. 2

   Remove the Wiper Arm

   From the outside of the rear window, lift the plastic nut cover, remove the retaining nut, and pull the rear wiper arm off the splined motor shaft.

3. 3

   Disconnect Wiring

   Unplug the electrical connector from the rear wiper motor assembly.

4. 4

   Unbolt the Motor

   Remove the mounting bolts/nuts securing the wiper motor to the cab frame or rear glass assembly.

5. 5

   Install the New Motor

   Mount the replacement motor and tighten the hardware. Reconnect the electrical harness.

6. 6

   Reassembly

   Reinstall the wiper arm on the outside of the glass. Secure the cab roof/headliner.

7. 7

   Test

   Turn the ignition on and test the rear wiper to ensure the open circuit fault code (520570-05) clears and the motor parks correctly when turned off.