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Author Topic: wm3677hw door lock problem  (Read 5433 times)

Offline kaylin_s

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wm3677hw door lock problem
« on: May 07, 2011, 05:47:56 PM »

I have a wm3677hw that has been having issues with the lock. so i replaced the lock mechanism. now the lock never disengages and constantly shows the door lock light on. when i turn the machine on and turn it off i hear it try to engage the lock mechanism 3 time. sometimes while the mechanism is engaging i can pull the door open but if i close it it is still locked. did i get a defective new switch or do i have a main pwb problem. Maybe does some one have a way to check the pin out of the door switch to see if it working properly.

Model WM3677HW

Offline krazytech

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Re: wm3677hw door lock problem
« Reply #1 on: May 07, 2011, 10:59:37 PM »
Is this a three wire door lock?

I would check how the door lock is mounted.. I believe the wires should be in the down position. this washer is very similar to the asko..
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Offline kaylin_s

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Re: wm3677hw door lock problem
« Reply #2 on: May 08, 2011, 09:01:47 AM »
unfortunately this is a 4 wire switch. i have heard a rumor there is some form bi metalic switch that prevents the lock from opening when its to hot.

Offline JWWebster

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Re: wm3677hw door lock problem
« Reply #3 on: May 08, 2011, 11:47:57 AM »
Some machines use a wax motor to latch the door. The wax is melted inside the mechanism. This expands it and pushes the lock closed. To get the door open after a complete cycle you must wait several minutes before attempting to open the door so that the wax motor can cool back down and retract the latch. The wax motor plays 2 roles. It locks the door and it also verifies to the control that it has done so or else the machine won't operate. Don't know if an LG has that but it does appear on the picture their are 2 wax motor type devices. I could be wrong.
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Offline Repair-man

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Re: wm3677hw door lock problem
« Reply #4 on: May 09, 2011, 12:22:16 PM »
All good tips, but  not appliacable. If the new lock assembly does not release  within 3 minutes of the end of the cycle, one would suspect the  main control.  It sends the unlock signal  as a last operation when it senses the motor RPMs  at zero. It also looks at water levels in the tub, but if you haven't had any other symptoms than this one, suspect the control.
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Offline ian_ian11

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Re: wm3677hw door lock problem
« Reply #5 on: May 09, 2011, 03:12:17 PM »
Prehaps the door itself is the problem. The door strike might not be fully disengaging. Could be a possibility that you have to replace the door strike. Or if you have slammed it shut or along those lines, you could have broken the switch and the door strike is catching onto the broken part of the door lock mech.

Offline scirocco.wind

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Re: wm3677hw door lock problem
« Reply #6 on: January 08, 2017, 01:08:57 PM »
I'm posting here for the benefit of future seekers of these answers...  having just been through extensive troubleshooting on this issue.

The WM3667HW has a four-wire door lock.  It is often, but not always the cause of problems.   IF you have replaced the switch, and find that it's the main board that is the problem, perhaps my experience will help.

Inside the switch has a small solenoid and a bimetallic strip which provide the mechanical motion for lock/unlock.

In my case, I went through a lot of trouble with the switch before discovering the issue was the main board.

Here's the pinout for the switch:

Black -- upper section of the main contact
Red -- lower main contact -- bimetallic strip -- solenoid
Blue -- solenoid (with resistor in circuit)
Yellow -- to resistor that heats bimetallic strip

You can figure out how it works by observation, but the practical upshot is that you can bypass the door lock altogether by jumpering the black and the red together.   

This is NOT SAFE since the door can now be opened during a wash cycle (messy) or spin cycle (can rip your arm off).

However, if you love the washer, don't have kids and are competent enough not to open the door this will work. 

If you want to take a shot at repairing your NLA main board, this is what I did:

The main controller board for my WM3667HW, part number 6871ER1003E is no longer available. It is potted in some kind of silicone. This is both a good thing and a bad thing.

The good part is that it makes it rather easy to spot parts that are burnt --- it darkens the goop and in fact makes it black and runny if the component gets hot enough. In my case it was the diode right next to the on-board transformer. I replaced it with an uprated version.


-- use a dremel to gently cut off the back of the plastic housing behind the bad component. Gently peel it up from the goop, do not stab into it!

-- Use automotive brake-cleaner to soften the goop. This will soften it without damaging any of the components or traces on the board. Apply liberally and often, soaking as necessary.

-- CAREFULLY use a pick to remove most of the goop. Strenuously avoid actually hitting the circuit board

-- Use a stiff-bristled brush to get the last bits off. A gun-cleaning brush (mil type) is pretty ideal. A stiff toothbrush will do.

-- Repeat on the frontside of the board. You may have to remove other components to get to the bad one. I had to remove the transformer.

-- Fix your board!

I love this washer, and it's no longer sold. It got some tough reviews and LG stopped selling because many people don't know how to use them, but for me it's awesome. I'll be limping mine along (bought 2005) for as long as possible.

« Last Edit: January 08, 2017, 01:20:24 PM by scirocco.wind »