Kenmore refrigerator defrost problem

The coils in my refrigerator are frozen over. Earlier this week I found them frozen, so I defrosted them manually with a hair dryer on the cool setting and thoroughly cleaned all the dust from under the unit. I plugged it back in and everything seemed fine for a day or three. Now I found the coils are frozen over again.

Additionally, I heard a clicking sound every few seconds this morning. It clicked 10-15 times or maybe more. It clicked for awhile; maybe minute or so. The click is coming from the top of the fridge, from a covered area behind the temperature control knobs. I believe it is the relay in the defrost control timer trying to send current to the defrost heater.

My next plan is to defrost the coils again and test the heater for continuity. If I find the continuity reading near zero on my multimeter, that would suggest that the heater wires are fine, correct? What else could be the cause of the defroster not functioning appropriately and causing the defrost timer relay to click? Or could it be something other than the relay that is clicking?

Thanks!

 

The refrigerator is a Kenmore Coldspot 106.59509990. Side-by-side with ice and water in the door.

 

We clean the coils in our rentals one time. If that doesn't solve the problem, we order our tenants a new fridge.

 

Unfortunately cleaning the fridge won't help that problem.
You have a defrost problem.
If you hear the defrost timer board rapidly clicking.... it may be bad.
original part # 2188159
replacement # 4388932

You can check the defrost heater with a meter but you also need to check the defrost thermostat which is attached to the evaporator coil and must remain ice cold to test. It is shorted below 40°.

Do you have the tech sheet ? It's inside the fridge... either behind the kick plate or in the back near the compressor. I'll post a temporary link below. There is a diagnostic routine for testing defrost.

Tech sheet # 2203946(HJ) ...... Tech sheet - pdf link

 

First try to force a defrost cycle.
If it defrosts then the heater and defrost thermostat are OK.

If it does not then do the meter checks of the components.

 

Thank you all for the responses. The defrost heater has continuity; resistance is 0.002 ohms or 0.005 or 0.003 depending on if I am wiggling when I test it. I removed it from the freezer and plugged it directly into power using a cord that is cut and barrel connectors fitted to the molex connectors. It drew 5 Amps and got real hot real quick.

The defrost thermostat showed 3.7 ohms of resistance at room temperature. Unfortunately I am not able to test it at freezing temperature.

I reinstalled everything and replaced the defrost timer. Now it doesn't cool it all. I suspect I damaged the coils while was was fighting it to remove the defrost heater for the testing I mentioned above.

The fridge is landfill now.

Thank you all for the responses! I spent way more time and money troubleshooting a 23 year old fridge than I should have, but I am satisfied that I did everything I reasonably could to save it. Thanks again to the community.

 

Sorry I missed this.....

The thermostat should be close to 0 ohms when cold and open at room temps.