Case IH 12527 – Cab Control Module (CCM) or Transmission/Drivetrain ECU: Right brake pedal switch fault – electrical signals are inconsistent

The control module is receiving inconsistent, illogical, or erratic electrical signals from the right brake pedal switch. This typically means the switch is sending conflicting open/closed states, or the voltage is dropping out of the expected range. This condition is usually caused by a failing internal switch mechanism, a misadjusted switch plunger, or a wiring harness issue (such as a short or open circuit).

• Puma Series (165, 200 CVT)
• Maxxum Series (110, 135, MXM190, older 51/52 series)
• Farmall Series (85C, 95C, 105U, 120C)
• JX Series (JX70, JX90, JX1090U)
• Optum Series

1. 1

   Visually and mechanically inspect the right brake pedal switch to ensure it is not loose, misaligned, or physically broken, and verify the pedal arm properly depresses and releases the switch plunger.

2. 2

   Perform a switch function test by disconnecting the switch and using a multimeter to verify it correctly opens and closes as the pedal is actuated. Erratic readings indicate a faulty switch.

3. 3

   Check for 12-volt power at the right-hand brake switch harness connector with the ignition key in the ON position. If 12V is missing, trace the wiring back to the fuse panel.

4. 4

   Inspect the wiring harness for rodent damage, chafing against the cab floor, or corroded pins in the connectors.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical shorts or accidental spikes to the ECU.

2. 2

   Locate the Switch

   Locate the right brake pedal switch under the dashboard/cab console, directly engaging with the right brake pedal linkage.

3. 3

   Disconnect Wiring

   Unplug the electrical wiring harness connector from the switch.

4. 4

   Remove the Old Switch

   Loosen the mounting nuts or retaining clips holding the switch in its bracket and slide the old switch out.

5. 5

   Install the New Switch

   Insert the new switch into the mounting bracket. Thread the mounting nuts but do not fully tighten them yet.

6. 6

   Adjust the Switch

   Adjust the depth of the switch so that the plunger is correctly depressed when the brake pedal is in its resting (unapplied) position. Once aligned, tighten the mounting nuts securely.

7. 7

   Reconnect and Test

   Reconnect the electrical harness and the battery. Turn the key on and test the brake pedals (both latched together and independently) to ensure the brake lights operate correctly, the tractor registers the braking action, and the fault code clears.