Case IH 520560-06 - BCM – BCM: Cab left wiper motor - short circuit to ground

The control module has detected that the electrical circuit supplying power to the left cab windshield wiper motor has shorted directly to ground. This means the voltage is bypassing the motor load and going straight to the chassis/ground, which typically causes a blown fuse or prompts the module to disable the circuit to prevent wiring damage.

• MAGNUM AFS Connect
• Magnum 250 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Turn off the ignition key and inspect the cab relays, circuit breakers, and fuses related to the wiper motor circuit. A blown fuse confirms the short-to-ground condition.

2. 2

   Inspect the wiring harness running from the BCM to the left wiper motor (often routed through the cab roof/A-pillar). Look for chafed insulation, pinched wires, or melted spots where the power wire might be touching the metal cab frame.

3. 3

   Disconnect the electrical connector at the wiper motor. Using a multimeter, check for continuity between the power supply wire in the harness and a known good chassis ground. Zero or very low ohms indicates the short is in the wiring harness.

4. 4

   If the harness tests good, check the internal resistance of the wiper motor across its terminals. An abnormally low ohmmeter reading indicates an internal short within the motor windings.

1. 1

   Disconnect Power

   Turn off the ignition key and disconnect the battery to prevent electrical spikes.

2. 2

   Remove Wiper Arm

   From the outside of the cab, remove the retaining nut and pull the wiper arm and blade off the motor pivot shaft.

3. 3

   Access the Motor

   Inside the cab, remove the cab ceiling trim/headliner panel to access the wiper motor framework.

4. 4

   Disconnect Motor

   Unplug the electrical connector from the faulty left wiper motor.

5. 5

   Remove Hardware

   Remove the mounting nuts securing the motor unit to the cab framework. Caution: Always use appropriate tools to align fixing holes during removal and installation. Never use fingers or hands to align the linkage.

6. 6

   Install New Motor

   Position the new wiper motor and secure it with the mounting nuts.

7. 7

   Reassembly

   Reconnect the electrical connector. Reinstall the cab ceiling trim panel.

8. 8

   Final Steps

   Reinstall the wiper arm and blade on the exterior. Reconnect the battery and test the wiper operation in all speed positions.