Coils freezing up on upper portion of LG refrigerator

Refrigerator & Freezer Repair
1

Hello,

I have an LG french door refrigerator model number LFX31925ST with the upper coils in the refrigerator section freezing up every couple of months. I have had LG change multiple parts in different service visits under warranty with no fix to the problem. Now it is out of warranty. They have replaced control boards, upper unit fans, etc. I measured 83 ohms on the 0 to 200 ohms scale on the defrost heater assembly (MEE62105201). Does this indicate that the coil is good? Can I test this by putting 120 volt A/C into the coil to see if it heats up? If the coil is good and there is a problem on the timer or control board please indicate. If I can run 120 volts directly across the coil then I could put a separate timer with outside A/C to run, if so how long should I run the heater coil each day to keep from freezing up. Right now I just defrost with a blow dryer every couple of months.

Thank you.

3

I have not worked on one of these units but perhaps the following will help.

Below is a good site
http://appliancejunk.com/forums/index.php

Join the site and be logged in .
Then search the entire forum (upper left corner) for LFX31925.
Post 2 that came up has a link to a service manual (tech booklet attached).

Page 31 in the manual says the defrost heater should be in the 34 to42 ohm range.

It looks like there should be a fuse in line with the heater.

I would also check the sensors.

Note that when checking resistances it is always a good idea to disconnect the device you are checking otherwise you could be reading an alternate/parallel circuit.