from the 16026365.pdf Tech Sheet:

Service Test Mode:

The service test functions are performed using the refrigerator display and keypad.

Enter the Service Test Mode by performing the following sequence of events.

1. Open the Fresh Food door and press and hold the Door Alarm keypad.

2. Press and hold Refrigerator Temperature UP keypad .

3. Release the Door Alarm Keypad and wait 3 seconds.

4. Press the Refrigerator UP Keypad again.

5. Display will show 001 in left display and numeric or dashes in right display.

6. Press Freezer Up keypad and Freezer Down keypad to toggle through Service Test numbers.

Service Test – 112 Freezer Fan

• Press the Refrigerator Up keypad and Refrigerator Down keypad to toggle Freezer Fan On and Off.

NOTE: Display will show state OFF or DC voltage.

Service Test – 121 Damper Operation

• Press the Refrigerator Up keypad and Down keypad to toggle Damper (OP) open and (CL) closed.

NOTE: If damper is opening or closing it will not allow you to toggle damper and beep. Display will show state –CL or –OP if Damper is in the process of closing or opening.

Source: maytag refrigerator MFD2561HES not cooling, fan running fine