Fendt 10.1.3C – A038 - ECU, Central Electrical System: B073 - Sensor, solar (irradiation) / Solar thermal radiation sensor

Function non-operable. The B073 sensor regulates the automatic air conditioning characteristic according to the level of sunlight (heat insolation) entering the cab. When this sensor fails or the circuit is interrupted, the system defaults to preset parameters. The central electrical system regulates the automatic air conditioning using a replacement value (typically 7 W/mm²).

• 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 (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III, SCR, S4, G7)
• Fendt 800 Vario (COM III, S4)
• Fendt 900 Vario (COM III, SCR, S4, G7)
• Fendt 1000 Vario (G4)

1. 1

   Locate the B073 sensor in the cab, on top of the steering column near the windscreen.

2. 2

   Check separation point X1535 (the connector for B073) for corrosion, backed-out pins, or moisture.

3. 3

   Measure supply voltage at the connector: should read 0 VDC with ignition OFF, and 5.0 VDC with ignition ON (supplied by the A038 ECU).

4. 4

   Measure signal voltage: should fluctuate based on brightness (approx. 80-90 mVDC or 0.28 VDC in dark surroundings, and 2.0-2.4 VDC in bright surroundings).

5. 5

   If the 5V supply and ground are good but the signal voltage is out of range or dead, the sensor has failed internally.

1. 1

   Turn off the tractor ignition and remove the key.

2. 2

   Depending on the exact Vario model, you may need to detach the steering column air box and remove its cover to access the sensor wiring.

3. 3

   Locate the B073 solar sensor at the top of the dashboard/steering column facing the windscreen.

4. 4

   Disconnect the electrical connector (X1535).

5. 5

   Carefully pry or unclip the faulty B073 sensor from its mounting aperture.

6. 6

   Snap the new OEM solar sensor into place.

7. 7

   Reconnect the X1535 wiring harness connector.

8. 8

   Reinstall any removed covers or air box components.

9. 9

   Turn on the ignition and use the Fendt Vario terminal diagnostics menu to clear the stored 10.1.3C fault code.

10. 10

    Test the automatic air conditioning system in direct sunlight to ensure the blower and temperature regulate correctly.