Case IH 1079 – Transmission ECU: Right External Fender Switch Unexpected Value

The control module is receiving an 'unexpected value' from the right external fender switch, meaning the voltage signal returning to the controller is outside the normal operating parameters, but it is not a complete open circuit/short to ground or a direct short to battery voltage.

• MAXXUM T4E
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 85C
• Farmall 95C
• Farmall 105C
• Farmall 105U
• Farmall 115U
• Maxxum 100
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Maxxum 150
• Puma 125
• Puma 130
• Puma 140
• Puma 145
• Puma 160
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Magnum Series

1. 1

   Visual Inspection: Inspect the right rear fender switch for physical damage, cracked rubber boots, or water/dirt ingress, which commonly causes resistance issues.

2. 2

   Wiring & Harness Check: Trace the wiring harness from the right fender switch back to the main cab harness. Look for chafed wires, pinched lines under the fender lip, or loose retaining clips (e.g., clip part # 47505757).

3. 3

   Connector Check: Disconnect the switch and inspect the pins for corrosion, moisture, or bent terminals.

4. 4

   Voltage/Resistance Test: Verify that the switch is receiving the correct 5V reference voltage and has a solid ground. Test the switch's resistance across its states (Up/Down or On/Off) to see if the internal contacts are degraded.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent short circuits or accidental hydraulic movement.

2. 2

   Access the Switch

   Locate the faulty switch on the right rear fender. Depending on the model, you may need to remove a small protective panel or mudguard backing to access the rear of the switch.

3. 3

   Disconnect Harness

   Unplug the electrical connector from the back of the switch.

4. 4

   Remove the Switch

   Depress the retaining tabs or remove the switch clamp/mounting screws holding the switch to the fender housing. Push the switch out of the fender bezel.

5. 5

   Install New Part

   Snap the new switch into the fender cutout and secure it with the clamp or retaining tabs.

6. 6

   Reconnect

   Plug the wiring harness back into the switch, ensuring the weather-tight seal clicks into place. Secure any loose wiring with clips.

7. 7

   Test

   Reconnect the battery, turn the key on, and test the external hitch/PTO function to ensure the system operates correctly and the 1079 code moves to an inactive state or clears.