Case IH 597-04 - UCM – UCM: Top of brake switch right voltage low

The voltage signal coming from the top switch of the right brake pedal is falling below the expected operational range. This typically points to a short to ground in the wiring harness, a disconnected plug, or an internal failure of the brake switch itself.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series
• Case IH Early Riser 2000 Series Planters

1. 1

   Check System Voltage & Grounds: Verify battery voltage is above 12.6V and check the main ground straps under the cab to rule out false voltage codes.

2. 2

   Inspect the Harness: Visually inspect the wiring harness leading to the right brake pedal switch. Look for chafing, pinched wires, or exposed copper that could be shorting to the chassis (ground).

3. 3

   Check Connectors: Unplug the connector at the right brake switch and at the UCM. Inspect for water intrusion, dirt, or pushed-out pins.

4. 4

   Test the Switch: Use a multimeter to test the continuity and resistance of the top right brake switch while actuating the pedal to see if it is functioning within range or if it has failed open/shorted.

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery terminal to prevent electrical spikes to the UCM.

2. 2

   Access the Switch

   Locate the right brake switch assembly, which is mounted at the top of the right brake pedal linkage inside the cab.

3. 3

   Disconnect and Remove

   Unplug the electrical connector from the switch. Unbolt or unclip the faulty switch from its mounting bracket.

4. 4

   Repair or Replace

   If the diagnostic checks revealed a short in the wiring, repair the damaged section of the harness and apply heat-shrink tubing. If the switch failed the multimeter test, install a new OEM brake switch.

5. 5

   Reassemble

   Mount the new switch, ensuring it is properly aligned with the pedal linkage so it actuates correctly. Reconnect the wiring harness.

6. 6

   Calibrate and Clear

   Reconnect the battery. Turn the key on and use the AFS Pro display or a diagnostic service tool to clear the inactive 597-04 fault code. Test the right brake pedal to ensure the code does not return and the brake lights/functions operate normally.