Case IH 3997-00 - BCM – BCM: Electrical Accessory Power Relay

An over-current situation or a short-to-ground on the accessory request circuit (FMI 6: Over Current). This occurs when the electrical draw on the accessory circuit exceeds the relay's rated capacity, typically caused by plugging too many aftermarket accessories into the cab's power ports, a short circuit in the wiring, or a degraded relay.

• MAGNUM AFS Connect
• Maxxum Series: 100, 110, 115, 120, 125, 130, 140
• Puma Series: 115, 125, 140, 150, 155, 165, 180, 195, 210, 225
• MX / MXM / MXU Series: MX100 to MX170, MXM120 to MXM190, MXU100 to MXU135
• CX Series: CX50, CX60, CX70, CX80, CX90, CX100
• Steiger Tractors
• Magnum Tractors
• Combines: 2144, 2166, 2188, 2344, 2366, 2388, 2577, 2588

1. 1

   Unplug all aftermarket monitors, radios, auxiliary lighting, or other devices connected to the cab's accessory power ports and cycle the key to see if the fault clears (verifies if the circuit was simply overloaded)

2. 2

   Locate the accessory power relay and inspect it for signs of overheating, melted plastic, or burnt pins

3. 3

   Use a multimeter to check the electrical accessory request circuit for a short to ground

1. 1

   Turn off the tractor's ignition and disconnect the battery

   This prevents electrical arcing or further module damage.

2. 2

   Locate the cab electrical fuse/relay panel

   On many Case IH models, this is located under the right-hand side console.

3. 3

   Identify the specific Accessory Power Relay

   Use the fuse panel diagram to identify the specific relay.

4. 4

   Remove the faulty relay

   Pull the faulty relay straight out of its socket.

5. 5

   Inspect and clean the socket terminals

   Clean away any dust or light corrosion, and ensure the female terminals are not spread too wide (which causes high resistance).

6. 6

   Install the new relay

   Plug the new 12V 5-pin relay firmly into the socket.

7. 7

   Reconnect the battery and verify repair

   Turn the key switch to the ON or ACCESSORY position to verify that battery power flows through the switch to energize the relay and power the cab accessories without triggering the fault code.