hi welcome to how to the pair this article is on how a washing machine door lock works and how to test a door lock or door into lockers there called in the 28 there are literally hundreds of different types of door interlock fitted to all the manufactures washing machines understanding how they work will give you a good idea whether you have a faulty door interlock on your machine most door locks only have three terminals on them a life a neutral and a common but on occasions you do get a door lock which has got four terminals this might be going to an LED to actually explain you that the door is open or shut.
like this one on the bottom the problem is with most modern machines the new interlocks only have numbers written on them unless you have a wiring diagram you do not actually know whether it’s my lives a neutral all the common so we have to actually try to work this out using a meter, on some washing machines they actually fitted a door interlock which was quite clever day fitted one with a cable attached to the bottom of it now this cable you were able to pull that would be hidden behind the kick strip in case of an emergency to open the door and rescue clothes, the only will check you can do to a door lock outside and parameters have an electrical field is to actually check the PTC heater this heats the bi-metal strip inside the door lock which then activates the door switch.
on this door lock I know that the actual terminals for live a neutral all number two a number three this is because I have the wiring diagram for this machine the common is number four.
now the problem being is most people would assume that that the connections all the same the actual live from neutral and common on all door locks are different on this door look for example, it is not on them the two or three, it is on them but three a number four as different manufactures use different suppliers for door locks you should never assume from the color the Wiring that it is alive common or neutral you should always look clearly at the door lock all the wiring diagram to ascertain whether this is the neutral live or common. most modern door locks have plugs the can only be fitted one way so in other words the Wiring is always collect so if you are trying to put spade connectors onto an old burnt plug, make sure you know what you’re doing! because not only will you blow the new door interlock that you are trying to fit you would also do damage to the circuit board as you can see with this older type door lock it is clearly marked see c, n, l meaning that the circuit on the right which I’m testing here which is intermittent, looks I know this door lock is faulty and that is clearly marked L and n for live and neutral and i know the common is the one on the left and as you can see this tall look sometimes you’re getting a reading and sometimes you don’t I have actually cut this door lock apart to actually explain you it working when I wire it up to my test rig now the wire or the terminal to the left is the neutral the one in the middle is all live feed and the one to the right is our common the as I said earlier these do vary from machine to machine so the one on the left here is on neutral the one on the right is the common and the one in the middle is the life feed now what actually happens is when live and neutral heat up the PTC heater it will heat the by a metal strip which will then move the mechanical parts of the switch which I’ll explain you in detail in the second. my test box is actually wired up with the switching on the neutral the live is constantly life and the yellow goes to a lamp so as we throw the door switch over as to simulate the door closed it will activate the light after the bimetal step has been heated up inside the door lock there is also a locking pin which is thrown over as the common is activated this actually keeps the door locked and keeps it locked even after the machine has finished for roughly two minutes this is why you can never get into your machine at the end of the cycle straightaway so the neutral is going to be switched the live is constant and then once we’ve pushed the door lock over to simulate the door being closed the power will then go through the yellow wire to the lamp. explaining that the machine has got a live circuit as the by metal strip is heated it pushes the switchover but the lamp only comes on if the door was shut so we just shutting the door that I’m a light comes on this explaining that we have now power being allowed to pass from the live to the common to activate the rest to the machine I will explain you in more detail to buy metal strip heating up and here goes the switch and it throws it over now this also activates the pin that locks the door in place at the end to the wash cycle even though the machine has finished its cycle it will not allow you to open the door for the roughly about two minutes while the bi-metal strip cools down when the bi-metal strip has cooled down in two minutes the lamp will go out while waiting for this to cool down please remember that all links on the left hand side at this article and also in the description for mobile users the link at the top will take you through to our shop where you’re able to purchase the door lock for your appliance please remember you will need your full model number of the identification plate on the machine do not assume that is the number on the facial panel as sometimes the numbers do fairly the other two links at the bottom will take you through to the full tutorial for this article which has extra articles on how to fit door locks on how to open the door to is stuck shot.
please also the remember to subscribe to our website as that’s what keeps us going in able to make this we article for you. you can see the like going out here now that means that the power has been cut from the feed to the common, but as you can see the switch has not gone down which locks the door as soon as you touch the door handle or press the door release button it takes the pressure off this switch and it pops back in one of the common problems when a door lock fails is the plastic inside a lock can distort this means that the end to the wash cycle when you come to release the door to get your clothes out. you can’t open the door on this issue lead you to the plastic distorting but you can see how little pressure is needed to the lease the door the light has now gone out so as soon as we touch the door handle in other words sliding the slider over here just to release the pressure of this pin it pops back into place, now if the plastic was distorted it might not pop back into the mechanism therefore keeping your machine locked behind the back of this cover which I’ve had to keep on to actually making the switch work is this tip of the points, this makes the electrical contact between the live and the common and the pin that you can see that goes up and down actually locks the door in place and as I said on this door lock alive is always active when the machine is switched on but only allows electricity to pass through to the common when the door lock is switched and there you go thanks very much indeed for reading this article please remember to support the website whether you buy the parts to less subscribe to the website: more even donate by buying us a beer thanks very much indeed for reading this article and please remember to visit the website thanks again do do do on did