Case IH 37 – TMF: The ARU reports EDC Transport Lock is faulty or not available.

The Armrest Unit (ARU) is unable to detect a valid signal from the Electronic Draft Control (EDC) Transport Lock switch. The fault indicates an open circuit, a short circuit, a failed switch, or an internal failure within the armrest control board.

• Magnum
• Magnum Series
• MX Series
• TG Series
• Series 4 235-340
• Puma Series
• Maxxum Series

1. 1

   Inspect the EDC Transport Lock switch/button on the armrest console for physical damage, sticking, or liquid intrusion (spilled drinks are a common cause).

2. 2

   Lift the armrest console cover and inspect the wiring harness connecting the EDC Transport Lock switch to the main ARU board for pinched wires, chafing, or disconnected terminals.

3. 3

   Using a multimeter, test the EDC Transport Lock switch for proper continuity when toggled. If it does not show a change in state, the switch is dead.

4. 4

   Verify that the switch is receiving the correct reference voltage from the ARU and has a good path to ground.

5. 5

   Disconnect the main harness at the Armrest Unit and check for bent, pushed-out, or corroded pins.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Armrest

   Remove the retaining screws securing the top cover or side panel of the multicontroller armrest to expose the internal EDC switches and the ARU circuit board.

3. 3

   Remove the Switch

   Disconnect the electrical pigtail from the back of the EDC Transport Lock switch. Depress the retaining tabs on the sides of the switch body and push it upward/outward to remove it from the armrest bezel.

4. 4

   Install New Part

   Snap the replacement EDC Transport Lock switch into the armrest bezel and reconnect the electrical pigtail.

5. 5

   Reassemble and Test

   Reinstall the armrest covers. Reconnect the battery. Turn the key on, clear the stored TMF 37 fault code via the tractor's display monitor, and test the EDC hitch raise/lower and transport lock functions to ensure the code does not return.

6. 6

   Replace ARU Board

   If the switch and wiring tested perfectly during diagnostics, the fault lies within the ARU board itself, which will require replacing the Armrest Unit/EDC Electronic Board and having a dealer re-calibrate the armrest.