Fridge Thermostat Testing

Refrigerator & Freezer Repair
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My Fridge is a side-by-side. It has an adaptive defrost control module instead of a defrost timer. Also, its temperature set thermostat is in front and has a “long reach” sensor tube that reaches all the way to rear wall of the refrigerator and the air exchange damper to the freezer.

I’d like to perform the ohmmeter thermostat test they talk about in the Kenmore DIY manual I bought. However:

  1. Those thermostats are for refrigerators units mounted in the rear, use defrost timers, and don’t look like mine;
  2. I don’t seem to get the results they describe; and
  3. So I feel I don’t really understand what test conditions they are setting up, or what constitutes valid, or invalid results.

[Thermostat
P/N: WHIRLPOOL 2198202; AP3037004]

For example, I’m expecting that when the thermostat allows the fridge to cool, it acts like a zero ohm or nearly zero ohm resistor. If this is true, how close to zero must it be to be considered OK? Asked another way, when do we consider “almost zero” not close enough and thus faulty?

Then, when the fridge approaches the set temp, does it act like a dimmer switch or an ON-OFF switch? Asked another way, is there a measured value of resistance “we” consider OPEN or infinite that is not really OPEN?

Also, the "long reach stem? on the thermostat in my fridge has a cover on it its entire length. I assume this is an important part of it, but why? And how does one change the temp of the thermostat for the purpose of a test?

[Tube barrier, thernostat (fc)
P/N: WHIRLPOOL 2196003; AP3041744]

I hope there are others out there who want to know about this too, or who know and are willing to share their knowledge.

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ON-OFF switch

[QUOTE]Asked another way, is there a measured value of resistance “we” consider OPEN or infinite that is not really OPEN?
[/QUOTE]

It’s ether OPEN all the way or shorted (closed). It’s nothing more then a switch the operates on temp.

It helps to insulate it.

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[QUOTE=ApplianceJunk;880]ON-OFF switch

That’s as clear as an answer gets! Tks.

It’s ether OPEN all the way or shorted (closed). It’s nothing more then a switch the operates on temp.

That’s as clear as an answer gets! Tks.

It helps to insulate it.[/QUOTE]

OK. The cover starts a few inches from the body of the adjustable part of the thermostat and covers the entire rest of the thin [wire? | tube? | ? ] to where it wraps in a “J” or “U” shape and seemingly ends at the air damper in a Styrofoam part of the damper. So I’m wondering how the air temp is detected?

I haven’t removed the thin “?” insulated assembly from the Styrofoam to see if the “?” perhaps it pokes out of the covering underside where I can’t see it; so I’m assuming the “?” remains insulated to its end. My Kenmore manual states: “11 Turn the thermostat to the warmest position…14 Place your hand around the thermostat bulb, for about two-three minutes.” The picture does not look like my fridge’s thermostat at all in that region? To perform this kind of test, how/where might I safely apply heat and expect to activate the thermostat to “ON-Shorted” status?

Measuring the resistance across the electric terminals as directed in steps 9 through 19 has only proven to me that all the way CCW is OFF, “OPEN”, but move it the slightest bit CW from that position and the ohmmeter reads anything from tenth’s of ohms to K’s of ohms, i.e. jumps all over the ohms scale. This is not the “good/defective” test I’d hoped for, rather it’s not unlike real life and judgements about other things. :frowning:

I do draw the conclusion it’s a lousy resistor, and a lousy switch too. But the fridge runs with it, it just doesn’t always restart after a cooling period. It did find it had an intermittent defrost thermostat that was sticking ON sometime, and I felt lucky to catch it in that state. I have replaced it.

Now the restart problem seems to be more frequent, and moving or sometimes turning the thermostat control OFF, then ON to normal setting position, or further, will restart the compressor and fans. Is it reasonable to have both components to be a problem?

I did order a new thermostat and “cover” last night from “APPros.com” hoping that it’s the missing piece to solving my refrigerator problems. Assuming it is, I want to learn how I could/should have made this decision sooner and with a higher level of certainty. And if there was a cause and effect relationship between the two component failures, I’d like to know that and “understand” its process.

Thank you so very much for reading and answering my post. I’m sure glad I “fell into” this resource.

Regards - Tony.C