Massey Ferguson 03.02.98 – TECU: High Voltage On Auxiliary Valve Switch 7

Short circuit to 12 V. The signal wire for the 7th auxiliary valve switch (often a FingerTIP control or joystick button on the armrest) is receiving a constant 12-volt supply, which is outside its normal operating range.

• 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
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Inspect the wiring harness for the Auxiliary Valve Switch (located in the armrest console or on the joystick) for chafed insulation, pinched wires, or exposed copper that could be shorting to a 12V power source.

2. 2

   Disconnect the switch connector (e.g., the FingerTIP switch connector) and inspect for bent pins, corrosion, or moisture ingress that could bridge the signal circuit to a 12V pin.

3. 3

   Test the Auxiliary Valve Switch 7 itself for internal failure. An internal short inside the push button/FingerTIP switch will cause a constant high voltage reading.

4. 4

   With the switch disconnected, test the signal wire from the switch connector back to the TECU to ensure the short to 12V is not occurring within the main armrest wiring harness.

1. 1

   Power Down

   Disconnect the tractor's battery to prevent further electrical damage or accidental shorting during disassembly.

2. 2

   Access the Switch

   Remove the necessary trim panels on the armrest control console or the specific auxiliary valve control lever to access Switch 7.

3. 3

   Disconnect

   Unplug the wiring harness connector from the faulty Auxiliary Valve Switch.

4. 4

   Repair/Replace

   If the diagnostic checks revealed a short in the wiring, repair the affected section of the Auxiliary Valve Switch Wiring Harness or replace the connector. If the switch failed internally, remove the faulty push button/FingerTIP switch from the control assembly and install the new OEM switch.

5. 5

   Reassembly

   Reconnect the wiring harness to the switch and reinstall the armrest console trim panels.

6. 6

   Clear Codes

   Reconnect the battery, turn on the ignition, and use the tractor's onboard display or a diagnostic tool to clear the 03.02.98 fault code.

7. 7

   Test

   Actuate Auxiliary Valve 7 to ensure normal operation and verify that the fault code does not return.