Massey Ferguson 3.03.86 – TECU (Tractor Electronic Control Unit): High Amp Draw On Auxiliary Valve Switch 3 (TECU)

The electrical circuit for the 3rd auxiliary (spool) valve switch is drawing more current (amperage) than the system expects. This typically indicates a short circuit to ground (0 V) in the wiring harness or an internal short within the switch or the valve's solenoid.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7715S
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726

1. 1

   Inspect the wiring harness between the TECU (Armrest Autotronic 5) and the Auxiliary Valve Switch 3 (FingerTIP 3 control) for chafing, pinched wires, or exposed copper.

2. 2

   Use a multimeter to check for a short circuit to 0V (ground) on the signal wire for Valve Switch 3.

3. 3

   Disconnect the Auxiliary Valve Switch 3 and test it for internal shorts.

4. 4

   Inspect the solenoid valve connections at the rear of the tractor for the 3rd spool valve to ensure the high amp draw isn't originating from a failed solenoid coil.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Access the Armrest

   Carefully remove the cover panels on the Multi-Function Armrest to access the fingertip switches and the Autotronic 5 module.

3. 3

   Isolate the Fault

   Disconnect the connector for Auxiliary Valve Switch 3. Reconnect the battery and turn the key to the ON position. If the code changes from "High Amp Draw" to an open circuit/voltage code, the short is internal to the switch. If the high amp draw code persists, the short is in the wiring harness.

4. 4

   Repair/Replace

   If the switch is faulty, replace the FingerTIP 3 switch assembly. If the wiring is shorted, repair the damaged section of the harness or replace the armrest sub-harness.

5. 5

   Recalibrate

   After replacing the switch or repairing the wire, clear the fault codes. You may need to perform a valve calibration procedure, as a related code (03.03.87: Calibration Issue For Valve Switch 3) is often triggered after this repair.