Fendt 0F.1.17 – Central Electrical System ECU: Brake and tail light left

The system has detected that the left brake or tail light function is non-operable (typically due to a blown bulb, open circuit, or short circuit). As a safety fallback, the tractor's system may automatically switch the left tail lamp to a day-driving configuration or dip the brake light for night driving.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 300 Vario series
• Fendt Farmer 400 series
• Fendt Favorit 700, 800, and 900 series
• Fendt 700-900 SCR series
• Fendt 900 Vario (COM III)
• Fendt Farmer 200/300 series
• Fendt Favorit 500/600/700/800/900 series
• Xylon tractors

1. 1

   Inspect the left rear tail/brake light assembly for physical damage, cracked lenses, or moisture ingress.

2. 2

   Remove the lens and check the filaments of the P21W (brake) and R10W (tail) bulbs. A blown bulb is the most common cause.

3. 3

   Inspect the bulb socket contacts for rust or corrosion. Check the main wiring harness connector at the back of the light assembly for loose pins or broken wires.

4. 4

   Consult the tractor's circuit diagram (Sheet 13/14). Use a multimeter to verify that 12V (or 24V) is reaching the socket when the brakes or lights are activated.

1. 1

   De-energize

   Turn off the tractor and remove the key to ensure the electrical system is powered down.

2. 2

   Access the Bulbs

   Unscrew the retaining screws on the left rear tail light lens cover.

3. 3

   Replace Bulbs

   If a bulb is blown, replace it with a new P21W or R10W bulb. Clean the socket with electrical contact cleaner if slight corrosion is present.

4. 4

   Replace Assembly (if necessary)

   If the housing is heavily damaged or the internal circuit board/reflector is corroded beyond repair, disconnect the main wiring harness plug from the rear of the assembly.

5. 5

   Dismount

   Unbolt the old light assembly from the tractor's rear fender/mounting bracket.

6. 6

   Install New Part

   Mount the new OEM or Hella replacement light assembly, secure the bolts, and plug in the wiring harness.

7. 7

   Test

   Turn on the tractor, activate the running lights and brakes, and verify the left tail/brake light illuminates correctly.

8. 8

   Clear Code

   Access the multiple display on the instrument panel. Call up the stored fault codes and press the confirmation button repeatedly to clear the code from the terminal's active display.