Massey Ferguson 03.03.86 – TECU: High Amp Draw On Auxiliary Valve Switch 3 (TECU)

The system has detected an excessive electrical current (high amp draw) on the circuit for Auxiliary Valve Switch 3. This typically indicates a short circuit to 0V (ground) in the switch itself, the wiring harness connecting the switch to the controller, or the armrest FingerTIP controls.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• MF 6700 S
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• MF 8690

1. 1

   Inspect the wiring harness running from the armrest console (FingerTIP controls or joystick) to the TECU for pinched wires, chafing against the seat suspension/cab frame, or melted insulation

2. 2

   Disconnect the harness at Auxiliary Valve Switch 3 (often located on the armrest X307/X308/X110 junction blocks) and check for moisture, corrosion, or bent pins that could bridge the circuit to ground

3. 3

   Measure the resistance between the switch's power feed pin and ground with the switch disconnected (a reading of near 0 ohms indicates the switch is internally shorted)

4. 4

   Test the wiring between the switch connector and the TECU (e.g., Pillar harness/armrest harness junction X464) for continuity to ground to verify if the harness itself is shorted

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery's negative terminal to prevent further electrical damage during repair.

2. 2

   Access the Switch

   Remove the armrest cover panels to access the FingerTIP control modules and the auxiliary valve switches.

3. 3

   Repair or Replace

   If the wiring is shorted: Repair the damaged section of the harness using proper soldering and heat-shrink tubing, or replace the affected harness sub-assembly. If the switch is shorted: Remove the retaining clips/screws for Auxiliary Valve Switch 3 and install a replacement switch or FingerTIP module.

4. 4

   Reassemble

   Reconnect all harness plugs, ensuring they click securely into place. Reinstall the armrest covers.

5. 5

   Clear Codes & Calibrate

   Reconnect the battery. Use a diagnostic tool (such as AGCO EDT or Jaltest) to clear the 03.03.86 fault code from the TECU memory. You may need to perform a valve calibration procedure (which resolves related code 03.03.87).

6. 6

   Test Operation

   Start the tractor and operate Auxiliary Valve 3 to ensure the high amp draw fault does not return.