LG LFC20740 Refrigerator constantly beeping (and fridge not cooling)

[fpoitras]

Last night, our LG LFC20740 Refrigerator started beeping constantly, three times every 30 seconds, as if the doors were left open. The fridge light did not light up when I opened the doors and the fridge had stopped cooling.

- The doors are closed.
- The door gaskets seem to make good contact everywhere.
- The door switches work (after I unplug-replug the fridge, the fridge light works for a while and I am able to check that both switches turn off the fridge light when depressed).
- I tried unplugging the fridge for 5 minutes, but the beeping starts again one minute after replugging.

If someone knows (a) the solution to this or things I should check, or at least stop the beeping temporarily, please let me know. Fortunately, we have a second fridge in the basement that saved our life as we are hosting a Christmas eve party tonight. But it would be great if I could fix this.

Thanks in advance

Frank

[bigbuck]

sorry to hear about your refrig. your missing two letters @ end of model number. pls. send complete model number, & we will see if we can help you!
 
 
 
                                                 thank you

[fpoitras]

Hi, thanks for the quick reply. The complete model number is:

LFC20740ST

Frank

[bigbuck]

went to lg database, found out beeping do to temp. change, only way to find out what component went bad is to put into test mode: this test will test the each one. i attached the test mode procedure.
 
 
 
also if you see any error code like er-ds come up , let us know.
 
                                                       thank you

[fpoitras]

OK thanks. I saw that also in the fridge service manual that I found here.

I ran the tests and everything seems to work fine. The fridge and freezer started cooling again during the test1 period. But the beeping went on.

Since the beeps are the same as the "door open" beeps, I checked the voltage (as per the manual) for the door switches on the back of the PC board. I am getting 5V for the Freezer door, which means "door closed", but 0V for the fridge door(s). I then opened the plastic case at the corner of each door, disconnected the switch and shorted the grey wires on each connector to simulate the closed door situation and the beeping went on.

Temperature sensor problem, I will try and check that later on, I have to get on the cooking job.

In the meantime, I am re-running TEST1 every now and then to get some cooling.

[fpoitras]

Follow-up. A technician just came to look at the fridge. He is almost certain the problem is the main control PCB, but he cannot get it today. I should get the part tomorrow.

Main Control Board PCB Part # EBR36222901

I am grateful for the help and manuals I found here on this site. I am no technician, but I was at least able to have a good idea of how the fridge works. So thank you.

I also have an expensive LG dishwasher for which I had the LE code (wire cut in the door), two years after purchase. Just curious about LG appliances, are they known to be less reliable than other brands?

Frank

[bigbuck]

no, they just have problem like all the other makes. keeps us busy everyday.