Case IH 4232 – EHR (Electronic Hitch Control) module: Rear EHR fender switch active at key-on

The controller detects a closed circuit (an active command signal) from the external rear Electronic Hitch Control (EHR) fender switch the exact moment the tractor's ignition is turned on, locking out the system as a safety mechanism.

• Maxxum series (110 EP to 140 EP)
• Puma
• Magnum
• Optum

1. 1

   Ensure the operator or a bystander is not accidentally leaning on or pressing the rear fender switch while the ignition key is being turned.

2. 2

   Inspect the rear EHR fender switch for packed dirt, mud, or physical damage that is causing the button to mechanically stick in the depressed position.

3. 3

   Disconnect the wiring harness from the back of the fender switch and use a multimeter to test for continuity. It should be 'Normally Open'. If it shows continuity without being pressed, the switch has failed internally.

4. 4

   Probe the wiring harness leading back to the EHR controller for a short to voltage (12V+) or a short to ground, which would trick the controller into thinking the switch is being pressed.

1. 1

   Turn off the tractor ignition, remove the key, and engage the parking brake.

2. 2

   Locate the affected EHR fender switch on the rear fender.

   Clean the surrounding area to prevent debris from falling into the electrical connections.

3. 3

   Reach behind the fender (or remove the protective cover panel) and unplug the electrical connector from the switch.

4. 4

   Depress the retaining tabs on the sides of the switch body and push it outward to remove it from the fender housing.

5. 5

   If the harness is damaged (chafed wires causing a short), repair the wiring using OEM-approved heat-shrink connectors.

6. 6

   If the switch is faulty, insert the new replacement switch into the fender cutout until the retaining tabs click securely into place.

7. 7

   Apply a small amount of dielectric grease to the electrical connector and plug it into the new switch.

8. 8

   Turn the ignition key to the ON position.

   Verify that the fault code is no longer active.

9. 9

   Test the EHR system from the cab, and then test the external fender switch to ensure the hitch raises and lowers correctly.