Case IH 518852-04 - VCM – VCM / UCM: 12VH1 supply voltage low

Voltage has dropped below the 8V operational limit or the power input is completely off on the 12VH1 circuit, which supplies voltage to specific implement and hydraulic controls.

• MAGNUM AFS Connect
• Magnum 235-340 (Series 4)
• Magnum 400
• Steiger AFS Connect
• Quadtrac
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Planters

1. 1

   Check the 12VH1 circuit fuse (typically a 15A or 20A mini fuse located at F-015 or F-019 on Magnum/Steiger models)

2. 2

   Inspect the UCM/VCM power relays (such as the Implement Power Relay or Cab Power Relay) to ensure they are closing properly and supplying voltage to the fuse block

3. 3

   Inspect the wiring harness running from the VCM/UCM to the hitch raise/lower solenoids or pump reverse solenoids for chafing, open circuits, or shorts to ground

4. 4

   Test the resistance of the hitch raise/lower coils or pump reverse coils for an internal short, which will cause the 12VH1 fuse to blow repeatedly

1. 1

   Locate fuse and relay panel

   Turn off the machine and locate the fuse and relay panel (often located behind the operator's seat in the cab or under the right-hand console).

2. 2

   Locate 12VH1 fuse

   Remove the panel cover and locate the 12VH1 fuse (F-015 or F-019, depending on your model's specific block layout).

3. 3

   Inspect and replace fuse

   Inspect the fuse. If it is blown, replace it with a new fuse of the exact same amperage (15A or 20A).

4. 4

   Check for dead short

   Turn the key on. If the fuse blows immediately, or blows as soon as you command the hitch/hydraulics to move, you have a dead short in the circuit.

5. 5

   Disconnect solenoids

   Disconnect the electrical connectors at the hitch raise and lower solenoids (or pump reverse solenoids on SSL/CTL models).

6. 6

   Isolate short to solenoid or wiring

   Replace the fuse again. If the fuse does not blow with the solenoids disconnected, replace the shorted solenoid coil. If the fuse still blows, trace the 12VH1 wiring harness back to the VCM and repair the short to ground in the wiring.

7. 7

   Clear fault code

   Once the short is repaired or the fuse is replaced, use the Electronic Service Tool (EST) or the in-cab display to clear the fault code.

8. 8

   Verify repair

   Test the hitch or hydraulic operation to verify the repair.