Massey Ferguson 03.02.8A – TECU: High Amp Draw On Auxiliary Valve Switch 4 (TECU)

The system has detected a "High Amp Draw" on the circuit for Auxiliary Valve Switch 4. This specifically indicates a short circuit to 0 V (ground) on the switch's circuit.

• 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 Switch: Check Auxiliary Valve Switch 4 (often a FingerTIP switch on the armrest) for physical damage, sticking, or liquid intrusion which commonly causes internal shorts.

2. 2

   Wiring Harness Test (Short to Ground): Disconnect the switch and use a multimeter to check the signal wire running from the switch to the TECU for continuity to ground (0 V).

3. 3

   Check TECU Reference Voltage: Verify that the TECU is outputting the correct reference voltage to the armrest controls.

4. 4

   Isolate the Component: Disconnect the switch. If the high amp draw / short circuit code changes to an open circuit or out-of-range code, the switch itself is internally shorted. If the code remains unchanged, the short is in the wiring harness between the armrest and the TECU.

1. 1

   Power Down

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

2. 2

   Access the Armrest Console

   Carefully remove the trim panels on the armrest to access the underside of the FingerTIP control module (Autotronic 5).

3. 3

   Inspect and Repair Wiring

   If the diagnostic checks revealed a short to ground in the harness, trace the wire from Switch 4 back to the TECU. Look for pinch points, chafing against the seat suspension/armrest pivot, or melted insulation. Repair the wire using solder and heat shrink, or replace the affected harness section.

4. 4

   Replace the Switch

   If the switch was found to be internally shorted, unclip Auxiliary Valve Switch 4 from the armrest bezel, disconnect the pigtail connector, and install the replacement switch.

5. 5

   Reassemble and Calibrate

   Reconnect the battery. Turn the key to the ON position. You may need to perform a valve calibration procedure via the tractor's display terminal.

6. 6

   Clear Codes

   Clear the stored 03.02.8A fault code from the TECU and test the hydraulic remote to ensure proper operation.