New Holland TMF 34 – Hitch Controller (TMF): Hitch Slip Select Switch failed in the Armrest controller

The Tractor Data Bus has signaled that the slip select switch (SW202) has failed. The hitch controller receives this fault signal directly from the armrest controller. The failure mode is typically either a physical failure of the switch itself, a wiring short/open circuit, or a software execution error within the armrest controller.

• T6
• T7
• T8
• T9
• TG210
• TG230
• TG255
• TG285
• TN70V
• Magnum
• STX
• MX/TG series

1. 1

   Verify operation of the 3-position Hitch Slip Select Switch (SW202): Position A (OFF), Position B (Center / Slip select), and Position C (Momentary / Slip set)

2. 2

   Perform pinout and multimeter testing on the armrest wiring harness for SW202 (Pins 2 & 5: Switch power, Pin 3: Switch B+, Pin 4: Signal slip select, Pin 6: Signal slip set)

3. 3

   Check CAN Bus communication for other ARU (Armrest Controller) communication codes to rule out a broader CAN bus connection issue rather than a localized switch failure

4. 4

   Verify if the tractor's ARU requires a firmware flash or update from the dealer to resolve a software execution error

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical shorts while working on the armrest console.

2. 2

   Access the Armrest Controller

   Carefully remove the trim panels and retaining screws on the operator's armrest console to expose the internal circuit boards and switch wiring.

3. 3

   Inspect Wiring

   Visually inspect the wiring harness leading to switch SW202. Look for pinched wires, chafing, or loose connector pins. Repair any damaged wiring.

4. 4

   Test/Replace the Switch

   Using a multimeter, test the switch across its three positions based on the pinout. If the switch fails to show continuity in the 'Slip select' (Position B) or 'Slip set' (Position C) positions, it must be replaced.

5. 5

   Reassemble and Clear Codes

   Install the new switch, reconnect the wiring harness, and reassemble the armrest console. Reconnect the battery, turn the key to the ON position, and use the tractor's diagnostic display (or a dealer service tool) to clear the TMF 34 / HITCH 1020 fault code.

6. 6

   Calibrate

   Test the hitch slip system in the field to ensure the armrest controller is properly reading the slip percentage.