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LMXS30776D/01 Refrigerator compartment fans not working during normal operation

Olympian

Premium Member
Joined
Feb 17, 2018
Messages
2
Location
PA
Model Number
LMXS30776
Brand
LG
Age
1-5 years
Good Afternoon All,

I have recently come into possession of an LG LMXS30776D/01 French style four door refrigerator and it has a couple of problems that I am trying to figure out - the refrigerator compartment ventilation fan (the one that exchanges air through a filter) and the evaporator fan do not run during normal operation - the freezer evaporator fan does work though

Here are a few steps I have already taken to try and figure out the possible culprit:

Put the unit in test 1 mode where all of the fans are supposed to turn on, which they all do
Measured the output voltage to the fans while in test mode 1 on the PCB utilizing CON 6 pins 3 & 5 (read approx. 15v) and the feedback voltage using pins 1 & 5 (approx. 5v)
Checked the fans for free movement and no obstructions
Checked the resistance on the refrigerator compartment temperature sensor to make sure it was not reading too cold in turn telling the fans not to turn on comparing the values to the chart in the service manual
Tripped out and measured continuity on all of the door sensors having them read the doors as being closed (since I have read elsewhere that opening a door causes the fans to turn off and back on again when the door is closed)
Checked voltages again during normal operation utilizing the same COM 6 pins as previously mentioned (0v across pins 3 & 5 and 5v across pins 1 & 5)
Reseated all of the connectors on the PCB checking for loose wiring/connectors and loose/bent pins

It seems to me that something is telling these fans not to turn on but at this point I am at a loss - is there something else I need to check or could I have a faulty PCB?

Any help is greatly appreciated a
 
Last edited by a moderator:

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
106,343
Location
McMullen Valley, Arizona
Hi,

You posted the age of this unit as Less than 1 year old, is that true?

Did you read the owner's manual?

It says that filter fan is only suppose to run 10 minutes ON, then 110 minutes OFF.

Is everything is the refrigerator and freezer sections saying cool and working normal?

Jake
 

Olympian

Premium Member
Joined
Feb 17, 2018
Messages
2
Location
PA
Thank you for the reply - to answer your questions:

I've had the fridge a couple weeks now - it is actually almost 2 years old
I read about how the filter fan is supposed to operate and I switched it to "power" mode and it still does not work (only comes on in test 1 mode - which still doesn't explain why the refrigerator compartment evap fan doesn't run

As far as the whole thing cooling, that is an entirely different issue I am working on

Thanks!
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
106,343
Location
McMullen Valley, Arizona
Got it!

For the refrigerator evaporator fan motor, Yes, volt testing the output at the control board: CON6 - 3rd pin and 5th pin, Should be 8-14 volts. If not, change the board.

Here's the control board for your model you can order:
EBR78643409 Pcb Assembly,main


Jake
 
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