21 replies to this topic

[Sunlight Appliance]

Hello Everyone,

 

My client's LG refrigerator is experiencing warming temperatures (31 degrees freezer, 64 degrees fresh food compartment), as well as, the Er FF code indicating "freezer fan" malfuction. Inside the freezer there was ice build up on the back wall and quite a bit on the floor. Taking the shelving out required breaking some ice away. There was water in the ice tray indicating to me that the icemaker was cycling, even with the high temperature.

 

I pulled out the icemaker assembly and removed the panel that covers the freezer fan. I was expecting to find ice buildup around the fan, but found that nothing was obstructing the blades. By hand the fan would spin smoothly. According to the manual I downloaded from Reg (thank you!) the fan operates at high speed at initial power-up and regular speed when the door is open. It did not run at all. I unplugged the appliance for a bit and then plugged it back in. At first, the fan moved 1/4" or so. But, that was it. Then it moved again and stopped. Then it turned on for about 1.5 seconds and stopped permanently. Pressing in the door switch did not change this. The display returned to normal, but within the time frame noted by the manual was overtaken again by the Er FF code.

 

Here's where diagnosing gets difficult for me. I know that this fan is a variable-speed assembly. I believe it operates on DC voltage supplied by the main board. I don't know how to test the fan motor, or how to verify it's getting constant voltage or the right voltage. There are 3 tiny wires in the fan motor harness: Red, Black, and Purple. I attempted to get readings with my multimeter, but I did not understand what I was supposed to be looking for or what the proper readings should be.

 

I've done very well with GE Profile and Arctica refrigerators and I assume that these LG's are not super-different, however, this is my first one and it is a little overwhelming. I feel that I am right on the doorstep of figuring it out though.

 

By the way, the owner told me that the dispenser light bulb turned on when the "Er FF" code first overtook the display. He could not get the bulb to turn back off, so he backed it off a bit until it did turn off.

 

Defrost system is working.

 

I am not charging my client until I can give him a firm and factual diagnosis. If anyone can offer some clarity here, I would apply it immediately to the situation.

 

Thanks in advance

Edited by Sunlight Appliance, 07 December 2012 - 04:41 AM.

[Samurai Appliance Repair Man]

There was a service bulletin out on the fan in 2002, was upgraded.  
 
Check for fan voltage by checking for 7.5 to 16 Vdc between the purple and yellow wires on Connector 7 at the Main PWB.   Make sure the controls are set such that the fan should be running when you make this test.  If no voltage, then either bad PWB or light switch.    If you have voltage, replace the evap fan motor ==> http://www.repaircli...ber=LRSC26910SW
 

 
 
 
 
 

 
 
 

[Samurai Appliance Repair Man]

PMed you the LG service bulletin on troubleshooting Er FF error codes.  

[Sunlight Appliance]

UPDATE:

 

I downloaded the bulletin and saved this page and brought my laptop with me to my client's house. I pulled the fridge out from it's cubby and removed the cover on top of the fridge in order to get to the board. The owner was there with me and he said,

 

"Do you smell that?"

 

"Yes," I replied.

 

What we were smelling was akin to burning electronics. The board was putting off that smell.

 

Anyway, I tested for 7.5 volts or higher between the yellow and purple wires of connector #7 and got 2.27 vdc. I wasn't sure if the board would try to send proper voltage while in an error-state, but I knew that for the first 100 seconds or so of initial powerup the screen display would clear and, according to the service manual, the freezer fan is suppose to run at high speed. I had the owner unplug the appliance for me and wait about 10 seconds. He then plugged it back in and we got a series of clicks from the board and then the condenser fan turned on, followed by the compressor several minutes later. During the clicking, and soon after, I was getting 4.98 vdc between the yellow and purple wires, but then it would drop back off to 2.27 and hold as the screen display changed from looking normal to showing nothing but "Er FF."

 

I then bench-tested the door switch. The door switch harness has 2 plugs:

 

1 plug for two little red wires and 1 plug for a large red wire and large yellow wire.

 

When not depressed the switch has full continuity at both sides and is completely open at both sides when the switch is depressed. So, when the door is open it has continuity, whereas shutting the door interupts the circuit. I understand this will turn off the interior light, but shutting the door does something for the freezer fan too and I don't know exactly what that is.

 

Final thing I tried was pressing the test button on the main board. I got zero response from doing that.

 

My diagnosis was for a bad PCB/PWB (main board). Do you agree?

 

Is there a risk of having a GE-type problem in that the evaporator fan takes out the main board making it necessary to replace the 2 together?

Edited by Sunlight Appliance, 08 December 2012 - 07:35 AM.

[Samurai Appliance Repair Man]

Does sound like a bad PWB.  Can also test the motor by wiring in a 9-volt battery between the purple and yellow wires.  

[Sunlight Appliance]

That is such an awesome idea! I'm back in his area Sunday, so I will drop by and do this quick test!

[DurhamAppliance]

That is such an awesome idea! I'm back in his area Sunday, so I will drop by and do this quick test!

 Now remember the Great Samurai has all kinds of magical weapons and wonderous mystical tools that us normal folk don't have. So before you go running over there with a 9v battery trying to figure out the best way to connect it to the fan,  get yourself a 9 v battery snap connector and attach  a pair of multimeter probes (or spade connectors) to it . Probing (or connecting spade connectors) to the fan wires from the board or connector on  the fan itself will energize the fan.  Makes testing easy.  No need to cut/tape fan wires to battery or have one of Samurai's mystical tools.

Edited by DurhamAppliance, 09 December 2012 - 07:24 AM.

[Sunlight Appliance]

Is there a risk of having a GE-type problem in that the evaporator fan takes out the main board making it necessary to replace the 2 together?

 

Almost successful tonight. Really need an answer to the above question.

 

Put in the brand new PWB and it fixed everything. Freezer fan blowing nice and hard while the doorswitch was depressed, and, no more "Er ff" code overtaking the display. Just about everything went back to normal and client went ahead and set the temperatures to his liking. The only thing not normal was the dispenser light still is not working, but he said he could live without it and that he was just glad to have his fridge back.

 

2.5 hours later the dreaded phone call comes in: "The 'Er ff' code is back!"

 

Is it possible that moisture has gotten into the freezer fan motor and is causing a short, taking out the board? I am assuming that when I go back over there that fan is not going to be spinning and I'm gonna get readings showing low voltage output again at the yellow and purple wires.

 

Does the fan motor and PWB need to be replaced together? Is there something else going on?

 

How important is the dispenser light in all this? He said that when the Er ff code first appeared the dispenser light bulb came on and would not go off. With new board installed, doesn't come on at all. Bulb is good.

[DurhamAppliance]

The dispenser light failure is probably related to a failure in the user control and display board. This issue occurred with another display board on a different model. Maybe the same here. I'm not sure but something to check out. With regards to whether it is related to the pwb failure? Only God and Sensei John63 would know the answer to that.

Edited by DurhamAppliance, 17 December 2012 - 09:56 AM.

[Samurai Appliance Repair Man]

Yes, there is a risk that ANY peripheral component that communicates with the muthaboard could take out the muthaboard.  The technology used in LG refrigerators is exactly the same as that used in the GE units and any other brand with a muthaboard: it's a single-board computer (the muthaboard) with peripheral devices (sensors, motors, etc.) attached to it.  As such, they are all subject to the same failure modes.  The variations will be in how, exactly, the failures manifest on the muthaboard:  does it burn out R22 vs triac 3, or some such.  But as far as we're concerned, it doesn't matter because a blown board is a blown board is a blown board.  

[Sunlight Appliance]

Okay. Thanks for your help. I will post back what happens.

[tpoindexter]

This might be a silly but what the heck! If the fans good but that part of the board is bad could you use the battery till you got a board shipped to ya? Or would that affect the board in such a way that the compressor won't run?

[Samurai Appliance Repair Man]

That is a viable, temporary work-around. Good, creative problem-solving!

[certified tech group 51]

To be real creative, and to keep the system balanced........................Wire 4 or so, 9 volt battery's in parallel and  wire in series, a defrost terminator........................Attach the defrost terminator up in the regular location....When the unit goes into defrost the battery powered fan will stop when the terminator opens...The fan will start when the terminator gets cold enough, it will close the circuit..............This way the fan is not running all of the time, it will have a delayed stop and a delayed start...........

[kdog]

Everybody has a charger for their car battery - right ? ..............

[DurhamAppliance]

  wire in series, a defrost terminator........................Attach the defrost terminator up in the regular location....When the unit goes into defrost the battery powered fan will stop when the terminator opens...The fan will start when the terminator gets cold enough, it will close the circuit..............This way the fan is not running all of the time, it will have a delayed stop and a delayed start...........

Pretty cool. I may make one of these things but If I understand you correctly, wouldn't you need a defrost terminator with a really low open threshold?  

[certified tech group 51]

I would guess one that opened at 40 to 50 and closed at 20 to 30 degs................you can look thru the supco catalog and find the t-stat. that has a low and high combination for the best price....................A good common one is the SLT-45 or  SLT-55  the one that has the side clip over tube ( main item )......will fit almost all tubing sizes..... Basically, what ever ya got in the buggy.

[Sunlight Appliance]

Wow, you guys really took off with this thread.

 

Well, everything seems to have worked out. I did not need to order another board afterall. Surprisingly, the fan circuit still had good voltage at the board even though the fan itself was not functioning anymore. Putting in the new fan motor cleared this up.

 

Voltages are to be measured between blue and purple wires in order to get the 12 to 16 vdc reading on the bulletin. You get between 1 and 4 vdc between yellow and purple. Nevertheless, the original board was still bad because I tested all of them.

 

I bought you guys a 6 pack for your time on this thread and much needed help! Thanks a ton!

 

Edited by Sunlight Appliance, 29 December 2012 - 04:44 AM.

[DurhamAppliance]

With evap fan motor failures it's a good idea to advise customer you may have to replace the board and the fan. If you wind up only having to replace one, you'll be considered a hero. If you have to replace both, you'd be considered "extremely competent and highly knowledgeable. "

[DurhamAppliance]

UPDATE:

I downloaded the bulletin and saved this page and brought my laptop with me to my client's house.

Work a pad/tablet in your office budget and download (and dropbox) as many manuals as you can ....it will change your life. Not only that but I always have access to this site when on service calls. Large screen smartphone can work as well.

Edited by DurhamAppliance, 29 December 2012 - 01:23 PM.