Fendt 04.1.79 – A050 - ECU, basic control unit: H007 - Buzzer reverse travel output not in order

The system detects that the electrical current draw for the reverse travel alerter is excessive (greater than 2500 mA / 2.5 Amps) or there is a short circuit in the line.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III)
• Fendt 700-900 SCR series (2011+)

1. 1

   Locate the H007 reverse travel buzzer (typically on the back wall of the cab on the left side).

2. 2

   Inspect the wiring harness between the A050 basic control unit and the buzzer for chafing, pinched wires, or exposed copper that could cause a short circuit to ground. Pay special attention to separation point X1544.

3. 3

   Measure the current draw of the buzzer when activated using a multimeter. If it pulls more than 2500 mA (2.5A), the buzzer is internally shorted and failing.

1. 1

   Turn off the tractor and disconnect battery power

   to ensure safety while working on the electrical system.

2. 2

   Access the back wall of the cab (left side)

   to reach the H007 reverse travel buzzer.

3. 3

   Disconnect the buzzer from the wiring harness

   at connector X1544.

4. 4

   Remove the mounting hardware securing the faulty buzzer

   If the wiring harness visually passes inspection but the buzzer failed the current draw test (or tests as a dead short).

5. 5

   Install the replacement reverse travel buzzer

   and secure it to the cab wall.

6. 6

   Reconnect the X1544 wiring harness connector

7. 7

   Reconnect the battery, turn on the tractor, and clear the stored 04.1.79 fault code

   using the diagnostic interface.

8. 8

   Shift the tractor into reverse

   to verify that the buzzer sounds correctly and the fault code does not return.