CLAAS Id7892h / 7892h – EXT (A62) - External Function Module: Left Stop Light Signal Invalid or Missing via CAN Bus

The External Function Module has received no information from the stop lights, or it has received an invalid signal from the left stop light for more than 5 seconds via the CAN bus. As a result, the left stop light information is not available on the rear 7-pin ISO connector.

• Axion 800 series
• Axion 820
• Axion 850
• Axion 900 series
• Axion 920
• Axion 950

1. 1

   Check the CLAAS vehicle CAN bus network: Look for short-circuits to ground or open circuits in the CAN lines.

2. 2

   Check the CAN bus network communication module: Verify the status of the BDG (A103) module, which handles CAN messaging.

3. 3

   Check energy sources: Inspect fuses, power supply, and ground connections related to the lighting circuit and the EXT module.

4. 4

   Inspect the 7-pin ISO connector: Check for corrosion, pushed-out pins, or physical damage at the rear trailer plug.

1. 1

   Visual Inspection of the Left Stop Light

   Begin by checking the left tail light assembly. Inspect the bulb (or LED board) to ensure it is not burnt out. Check the local wiring pigtail for breaks or chafing.

2. 2

   Inspect the 7-Pin ISO Trailer Socket

   Open the flap on the rear 7-pin connector. Clean out any dirt, debris, or moisture. Use a multimeter to check for continuity and ensure the left stop light pin (typically Pin 6 / 54L on standard agricultural ISO 1185/3732 connectors) is not shorted to ground.

3. 3

   Harness Testing

   Trace the wiring harness from the left stop light and the 7-pin ISO connector back to the EXT (A62) module. Test for continuity and verify there are no open circuits or shorts to the chassis ground.

4. 4

   CAN Bus Verification

   If the physical wiring to the lights is intact, test the CAN bus communication lines between the EXT (A62) module and the BDG (A103) communication module.

5. 5

   Module Replacement/Calibration

   If all wiring, fuses, and bulbs test good, the fault likely lies within the EXT (A62) module failing to process the signal, or the BDG (A103) module failing to transmit it. Replace the faulty module and perform any required software calibration or parameter settings via the CLAAS diagnostic tool.