CLAAS Id7891h / 7891h – EXT (A62) - External Function Module: Position Lights Communication or Signal Failure

The external function module has received no information from the position lights, or it has received an invalid signal from the position lights for more than 5 seconds over the CAN bus. As a result, the position light information is not available on the rear ISO 7-pin implement connector.

• CLAAS Axion 800 Series
• CLAAS Axion 810
• CLAAS Axion 850
• CLAAS Axion 900 Series
• CLAAS Axion 920
• CLAAS Axion 950
• CLAAS Arion 600 Series
• CLAAS Arion 640

1. 1

   Check the ISO 7-pin connector for physical presence of the position light signal, corrosion, pushed-out terminals, or physical damage

2. 2

   Check the CLAAS vehicle CAN bus network lines for proper voltage and resistance to ensure messages can be transmitted

3. 3

   Check the BDG (A103) Module to ensure it is communicating properly on the CAN bus network

4. 4

   Check the EXT (A62) Module power supply, ground, and fuses

5. 5

   Inspect the wiring harness for short-circuits or open circuits between the lighting circuit, the EXT module, and the ISO 7-pin connector

1. 1

   Visual Inspection

   Start at the rear of the tractor. Open the flap of the ISO 7-pin connector and clean out any dirt or debris. Look for green corrosion on the terminals.

2. 2

   Test the Output

   Turn on the tractor's position lights. Use a multimeter to check for 12V at the position light pins on the ISO 7-pin connector.

3. 3

   Harness Continuity Test

   If there is no voltage at the connector, trace the wiring harness back from the ISO 7-pin connector to the EXT (A62) module. Repair any broken wires or chafed insulation causing a short to ground.

4. 4

   Module Power/Ground Check

   Test the power and ground inputs at the EXT (A62) and BDG (A103) modules. Replace any blown fuses and clean ground eyelets.

5. 5

   Software/Calibration

   If the wiring and connectors are perfectly intact, check the compatibility of the program versions. The EXT (A62) or BDG (A103) module may need a software re-flash by a CLAAS dealer.

6. 6

   Module Replacement

   If all wiring, CAN bus resistance (typically 60 ohms across CAN High and CAN Low), and software checks pass, replace the faulty EXT (A62) module.