[jcw2]

BACKGROUND:
8-year old fridge.
Fridge display panel read 37F for fridge and 5F for freezer.
My home thermometer reads 37F and 28F, respectively.
Ice maker stopped making ice.
Noticed ice in back of freezer, upper right corner, encasing thermistor.
Noticed a lot of lint under fridge on those coils.
Compressor seems to have normal operational duty cycle.

WHAT I DID:
Vacummed off coils under fridge.
Opened up back panel of freezer.
Noticed ice built up around upper right corner, around copper tube, and top of fins.
Melted ice with blow dryer.
Waiting to see if freezer can now get back to normal, 0F.

QUESTIONS FOR YOU:
What caused this problem? Lint on lower coils? Bad defrost thermostat? Bad defrost heater? (Can a heater really fail?) Or something else? Thanks.

NOTE: I do not have a multimeter. I do not want to buy and replace more parts than necessary.

[Gene]

Wait one or two more days to see if the cleaning helped. Make sure the back panel in the freezer is in place.

If the temperature is still not good, you have to buy a multimeter.

Let us know when you ready. Check the evaporator coils and post the result.

Here are the breakdown diagrams and Replacement parts for MAYTAG MFD2561HES REF - BOTTOM MOUNTS | AppliancePartsPros.com

Gene.

[jcw2]

Back panel was put back in place after defrosting with blow dryer, at 4pm local time. My fridge has been showing me these temperatures so far ...

5pm: 44F fridge and 33F freezer.
6pm: 41F fridge and 30F freezer.
7pm: 41F fridge and 29F freezer.
8:18pm: 40F fridge and 28F freezer.

Is it normal for temps to drop this slowly?

(Will get a multimeter, and give you status in about 24 hours.)

[Gene]

Let him stay for about 24 hours, then check it. Try not to open the doors.

Gene.

[jcw2]

It has been 48 hours since we defrosted him.
Fridge leveled out at 37F, freezer doesn't go below 28F.
Ice is reforming on the back (inside) of the freezer compartment.

What do you think?
Replace defrost heater and defrost thermostat?

Will that definitely fix him for good?

[jcw2]

Freezer levels out at about 28F.
Fridge achieves requested setting temperature of 37F.

Have manually defrosted the coils twice now.

Plan to replace defrost thermostat and defrost heater tomorrow (assuming that the ordered parts arrive).

Any comments?

[Gene]

Before you replace these two parts you may want to check them for continuity. It is possible that the problem is a bad control board (#5 on the diagram) and only continuity test on the defrost heater and defrost thermostat can help you to determine it.

Gene.

[jcw2]

Good idea.
I now have a multimeter.
I found your historic article on continuity testing, but if I recall correctly it did not explicitly cover fridges.
Can you provide a link to step-by-step testing of the defrost heater and thermostat? Or is it simple enough to describe in e-mail?

Heater:
(1) Disconnect both ends?
(2) Touch multimeter leads to what pins?
(3) For a good part, what reading should I get?

Thermostat:
(1) Should fridge power be ON or OFF?
(2) Are leads on thermostat exposed?
(3) For a good part, what reading should I get?

Thanks.

[Gene]

Originally Posted by jcw2

Good idea.
I now have a multimeter.
I found your historic article on continuity testing, but if I recall correctly it did not explicitly cover fridges.
Can you provide a link to step-by-step testing of the defrost heater and thermostat? Or is it simple enough to describe in e-mail?

Heater:
(1) Disconnect both ends?
(2) Touch multimeter leads to what pins?
(3) For a good part, what reading should I get?

Thermostat:
(1) Should fridge power be ON or OFF?
(2) Are leads on thermostat exposed?
(3) For a good part, what reading should I get?

Thanks.

The refrigerator has to be unplugged. Both the heater and the thermostat must be disconnected. You can cut a wire for the test and splice it together after. The thermostat must be ice cold. The normal reading for the thermostat should be close to 0 Ohms and for the heater between 20 to 40 Ohms.

Gene.

[jcw2]

Got readings of appx 0 ohms for the defrost thermostat, and about 23 ohms for the defrost heater. Replacement parts were already ordered, so I paid for them and installed them. I've got the fridge buttoned up and will see if my troubles continue.

If troubles continue, at least I can rule out those two items as possible culprits.