My eyes are shot. I’ve been reading related messages for hours now, but decided to post my specific issue. A couple week ago, I noticed frost on the back wall of the freezer. Additionally, I had a frozen layer of water on the bottom of the freezer compartment. I removed the back panel, defrosted with a hair dryer and ran hot water down the drain hole, since that was totally frozen solid. I got it to the point where I heard the water running thru the tube, into the drain pan. Put everything back and I thought "problem solved".
Today, I noticed even more frost on the back wall of the inside freezer. I do not have frozen water on the bottom like last time. This, I think, is telling me that this problem is a bit different. In my 1st problem, the unit was defrosting (because I got that layer of ice on the bottom), but wasn’t draining due to a frozen hole. In this case, it doesn’t appear I’m defrosting at all. Maybe I wrong and wasn’t defrosting in either case.
I’ve read about somehow manually forcing a defrost cycle or something like that. I don’t know how to do that. Also, something about tricking the defrost timer to engage. I’m thinking, based only on what I’ve read so far, that my defrost heater or defrost timer or defrost thermostat is shot. How do I go about narrowing it down?
First remove the evaporator cover in the freezer so you can see the coils.
Do not let them de-ice.
If they are heavily iced/frosted over you have a defrost problem.
If yes.
Manually force a defrost cycle by turning the defrost timer cam (Item 4 in Section 3) till the fans and compressor turn off.
There is usually a hole in the cover to let you do this with a screw driver.
Note: The cam only turns in one direction.
Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the timer needs replacing, re: it is probably stalling during it’s rotation so is never getting into a defrost cycle.
If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item 4 in Section 4) from the wiring and measure it for continuity, usually around 20 ohms or so.
If the heater is OK
Remove one wire to the defrost thermostat and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it.
Also inspect it, if it is bulged at all replace it even if it measures OK.
I could not see it in the parts breakdown. It should be clipped onto the evaporator coils. It hay even be hard wired into the heater.
If both the above are OK then odds are the defrost timer contacts are toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo.
If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
Always remove power from the machine otherwise you could blow your meter.
Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale’s dynamic range.
There is a good STICKY at the start of this forum about it’s use.
Thanks a bunch. It looks like this references a service manual or something as to procedures or locations. Is that the case and if so, where can I get that document? I reall appreciate the help.
Got it, thanks. Looks like that defrost timer is within that panel that’s on the roof of the refrigerator and I’ll have to take that panel down, unless there’s access straight thru the panel.
Good news. I was able to access the dial on the defrost timer without taking any off. A simple screwdriver up into the hole, turning clockwise until the fan shut off, immediately put me in defrost mode. The heater element is definitely working. Don’t ask me how I found out. :mad:
Anyway, I’ll order the defrost timer and perform a manual defrost once a day until I get it installed. I hope that’s not to big of a deal to replace. If you have any helpful hints on tackling that job, I’d appreciate it.
Does this mean that my timer is now doing what it’s supposed to do and no longer requires replacing?
I am afraid not.
There is still a problem in the unit and the timer is at the top of the list.
It could be that the timer will run OK for a couple hours and then stop.
This can be due to a gear in the timer missing a tooth or two.
Could even run OK for a couple days and then mess up.
In my opinion it has to ge a timer or the defrost thermostat but I am putting my money on the timer.
Does this mean that my timer is now doing what it’s supposed to do and no longer requires replacing?
I am afraid not.
There is still a problem in the unit and the timer is at the top of the list.
It could be that the timer will run OK for a couple hours and then stop.
This can be due to a gear in the timer missing a tooth or two.
Could even run OK for a couple days and then mess up.
In my opinion it has to be a timer or the defrost thermostat but I am putting my money on the timer.
Thanks for the reply. My replacement defroster timer did arrive, so it’s just a matter of replacing it. I was just curious as to whether the old one could have fixed itself by simply turning the cam by hand a few time agressively.
So, I did replace the defrost timer a few weeks ago. Things seemed to be going well, until I noticed the same issue of frost collecting on the inside back wall of the freezer again. Having a new timer in there now, what we be the next componant to replace?
Damn !!!
I would replace the defrost thermostat as they can go intermittent.
[part]AP3135377[/part]
Click on the picture for more views/info.
I’m not the handiest person.
You were able to replace the defrost thermostat so am handy enough to do the job.
I would try forcing a defrost again.
Who knows maybe the heater has burned out.
— End quote
Thanks. I guess I’ll try that. I can’t tell from the picture where it goes, although it appears to be part of the icemaker. Is that really the case? I thought it would be somewhere behind the back wall of the freezer.
I screwed up, you are correct that this is the wrong part.
You want to replace the bi-metal thermostat not this one. AP4303701
It is Item 25 in Section 3. It should be clipped onto the evaporator coils.
Looks like you have to hard wire it in.
Cut the wire to it close to the bi-metal.
Then use 2 wire nuts to connect it.
Then twist tie them away from the heater and facing down so water does not get into them.
As an extra precaution you could fill them with silicone sealeant but I would force a defrost just to be sure it is connected in properly.
hold the face of the bi-metal onto an ice cube to freeze it before checking as it opens just above freezing.