Important Diagnostic Consideration

TM 10-4110-262-13&P

0028 00

NOTE

Ensure Pin 9 (W) is properly grounded.

Symptom

Corrective Action

Blank display when the ON/OFF switch

Check for 24 VDC between Pin 2 (positive) and Pin 9

is pressed

(ground)

Check Fuse 4/1 located in the unit controller

Replace unit controller

Unit is not cooling when the IC interior

Check for 24 VDC between Pin 6 and Pin 9 (W)

temperature is higher than the setpoint

Check continuity on Fuse 4/1

temperature.

If no voltage, replace unit controller.

Unit operation LED is off when the unit

Check for 24 VDC on Pin 7

is cooling

Note the malfunctioning LED and continue to operate the

unit

Defrost cycle is not initiated when the

The unit must be indexed to cool (compressor on)

manual defrost switch is pressed

Evaporator coil temperature must be lower than 36 F at

the DTS.

Press the manual defrost switch and check for 24 VDC on

Pin 8.

Replace unit controller

0028 00-8