Possible Causes

2021 Ford Edge SE, 4WDSECTION Possible Causes
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
  • Wiring, terminals or connectors
  • Mode select switch
  • HVAC module concern
  • ABS module concern
CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
  1. OC1: CHECK FOR ABS MOUDLE DTCS 
    • Put the ABS module in sleep mode by performing the following steps:
      • With ALL doors closed, set the ignition from ON to OFF.
      • Disconnect the diagnostic scan tool.
      • Open the door, exit the vehicle and close the door.
      • Wait a minimum of 90 seconds for the ABS module to enter sleep mode.
    • Ignition ON, engine OFF.

      Carry out the ABS self-test.

    • Are there any DTCs currently active and present in the ABS module? 
      Yes No
      DIAGNOSE all ABS module DTCs before diagnosing the snow/sand mode feature. GO to the ABS module DTC Chart in this article. Go to  OC2.
  2. OC2: CHECK FOR HVAC MOUDLE DTCS 

    Carry out the HVAC self-test.

    • Are there any DTCs currently active and present in the HVAC module? 
      Yes No
      DIAGNOSE all HVAC module DTCs before diagnosing the snow/sand mode feature. REFER to the Climate Control System General Information article to diagnose the HVAC module. Go to  OC3.
  3. OC3: CHECK THE SNOW/SAND MODE CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Mode Select Switch connector disconnected.
    • HVAC_A Module connector disconnected.
    • Measure the resistance between:
      (+) Mode Select Switch Connector, Harness Side (-) HVAC_A Module Connector, Harness Side
      SND_MD SND_MD
    • Is the resistance less than 3 ohms? 
      Yes No
      Go to  OC4. REPAIR the circuit.
  4. OC4: CHECK THE SNOW/SAND MODE CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      (+) Mode Select Switch Connector, Harness Side (-)
      SND_MD Ground
    • Is the resistance greater than 10, 000 ohms? 
      Yes No
      INSTALL a new mode select switch. REPAIR the circuit.
  5. OC5: CHECK THE MODE SELECT SWITCH GROUND CIRCUIT FOR AN OPEN 
    • Measure the resistance between:
      (+) Mode Select Switch Connector, Harness Side (-)
      GND Ground
    • Is the resistance less than 3 ohms? 
      Yes No
      INSTALL a new mode select switch. REPAIR the circuit.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.