Possible Causes
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2021 Lincoln Corsair, 2021 Ford Transit-350 HD, 2021 Ford Transit-350, 2021 Ford Transit-250, and 2021 Ford Transit-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.
- OC1: CHECK FOR ABS MODULE 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. - Put the ABS module in sleep mode by performing the following steps:
- OC2: CHECK FOR HVAC MODULE 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 Climate Control System - General Information (1 Of 2) - F450 - F600 Super Duty and/or Climate Control System - General Information (2 Of 2) - F450 - F600 Super Duty article to diagnose the HVAC module. Go to OC3. - 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. - 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. - Measure the resistance between:
- 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. - Measure the resistance between: