Deutz-Fahr I24 – Instrument Panel / Dashboard module: Power output 0 short circuit to earth

The preheating control relay (glow plug timer device) is short-circuiting to ground. This prevents the engine's preheating system from functioning correctly, which can lead to difficult cold starts.

• Agroplus 310, 320, 410, and 420 Profiline series tractors
• Deutz-Fahr Agrofarm Series (e.g., 85, 100)
• Deutz-Fahr Agrotron Series (e.g., M600, 215, 230 MK3, 260 MK3, Series 6, TTV)
• SAME Explorer 90

1. 1

   Turn the starter key to the “O” (OFF) position.

2. 2

   Disconnect the main harness connector (e.g., connector "5K") from the instrument panel.

3. 3

   Connect a multimeter to the preheating control relay connector (e.g., pin 2 of connector "RL42") and the corresponding pin on the instrument panel connector (e.g., pin 19 of connector "5K").

4. 4

   Test the resistance to check for continuity (the meter reading should be 0 Ohms).

5. 5

   Test the relay power supply wire against the chassis ground to confirm if the wire itself is chafed and shorting to earth.

6. 6

   If the wiring harness is intact and shows no signs of grounding out, the internal circuitry of the preheating control relay has likely failed.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the Relay

   Access the tractor's main electrical control board or relay panel (location varies by cab/chassis configuration) and locate the preheating control relay.

3. 3

   Inspect Wiring

   Carefully inspect the wiring harness leading to the relay. Look for rubbed-through insulation, melted wires, or exposed copper touching the metal chassis. Repair any damaged wires using heat-shrink tubing and electrical tape.

4. 4

   Replace the Relay

   If the wiring is healthy, pull the faulty preheating control relay from its socket. Inspect the socket terminals for corrosion or melting. Plug the new OEM replacement relay into the socket.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery. Turn the starter key to the ON position to clear all passive alarms.

6. 6

   Test

   Cycle the ignition to activate the preheating system and verify that fault code I24 does not return.