Defrost Thermostat

Fridge is a side by side. The freezer is pretty narrow for a guy with wide shoulders.

Pulled plug.

Had to remove bottom drawers then used nut driver to remove screws closest to back wall in drawer runners. Once the back screws were removed the runners could be swung up or down out of way so back cover could be removed.

Once back cover was removed thermostat was located attached to top pipe going into coil using a spring clamp.

Cut the wires just outside the crimp connectors going into thermostat. Released the spring clamp buy squeezing botton together.

Removed old badly corroded thermostat.

I wish I had attached the crimp connectors to the new thermostat wires before mounting it. Reaching way in the back, while turning shoulders verticly and trying to get the wire connectors set from both sides was awkward and uncomfortable...The biggest PIA of the whole task.

Once connected I let the fridge (thermostat) cool for 10 min. Turned the dial defrost timer to get it into defrost mode. Stupidly touched the heating element to see if it was getting warm...it was very hot.

Coils steamed...every looked like it was working. Unplugged, put back cover back on and retattached drawer mounts.

Plugged back in and everying is working great!

First i killed the power and water supply to fridge. Then i removed all the racks in freezer and the 1/4" screws for rack supports with nut driver. Next i removed the evaporator cover 1/4" screws to gain access. Then i removed the the 1/4" screw that holds the evaporator at the bottom and moved the evaporator outward to remove the heater element. Then i installed new heater element from the bottom of the evaporator making sure it was in the center of the evap coils.
Next i replaced the defrost thermostat cutting the old wires. Then stripped and crimpped the new thermostat in place making sure of the same installed postion as removed.
Next i replaced the defrost timer located at the bottom left using philips head screw driver.
Next i replaced the water filter by turning it counterclockwise to remove.
Then restored power and water supply. Next i tested the heater element by turning the dial on the defrost timer clockwise until it clicked and watched the element glow.
Then waited for the deforst thermostat to shut off the heater. Finally i checked the evaporator drain iin the back of fridge for blockage and cleaned out completely.
Repairs successful fridge good as new.

Danger: Replacing these parts requires working with electrical wiring, be certain to unplug the refrigerator before starting work.

1. Unplug appliance
2. Empty freezer section
3. Remove shelves and Ice storage tray
4. Remove 6 screws from evaporator cover.
Note: Remember where the screws with insulated washers go.
5. Use a hair dryer to melt all ice from coil
Danger: To prevent injury or death from electrocution always ensure that the hairdryer does not get wet while in operation.
6. Unplug defrost heater and defrost thermostat wires
Note: Thermostat is wired in series with the heater.
7. Remove screw from white plastic holder located on top of evaporator coil
8. Remove styrofoam pieces from top of coil
9. Grasp the bottom of the evaporator coil and carefully lift and pull out the bottom end a few inches
10. Remove old heater coil by pulling out from the bottom and replace with new coil
Note: Be very careful when moving the evaporator, it is made of aluminum and will be very costly to repair if you damage the tubing.
11. Replace old thermostat with new thermostat
12. Re-connect thermostat and heater wiring
Note: Remember to route wiring so that condensation does not gravitate to the electrical connections.
13. You can check if the heater is working by manually rotating the defrost timer clockwise. The timer dial is located on the bottom, front of the refrigerator on the freezer side. Be careful, the heater gets very hot.
14. Re-install evaporator cover
15. Re-install shelves and ice storage tray
16. Plug in the refrigerator
Note: Depending on how warm your refrigerator was it may take 24 hours to return to normal operating temperatures.
Note: Take your time and the job will go faster.

I checked the defrost timer (bottom front of the freezer / outside). I advanced it to send it into the defrost cycle. The heating elements in the freezer (behind the panel) did not heat up. I cut the wires going to the defrost thermostat. Turned the power back on, made sure the defrost timer was still in the defrost cycle and checked the voltage at the wires to the defrost thermostat (before the heating elements). There was power / voltage there. I jumped out / bypassed the defrost thermostat turned the power back on and the heating elements came on. The problem was the defrost thermostat. So I replaced it with a new one from PartSelect.com. How it works...
When the defrost timer is advanced to the defrost cycle the switch closes sending power to the defrost thermostat. If the temperature is low enough, the defrost thermostat switch will close and sends power to the heating elements. When the temperature rises high enough about 55 degrees the switch at the thermostat will open and the heating elements will turn off (not allowing the freezer temperature to get too high, just enough to defrost the coil). The refrigerator will turn back on when the timer advances. The defrost timer will defrost every 8-12 hours.

I ordered a defrost timer and defrost thermostat from partselect.com. Parts arrived in 2 days (earlier than expected). Unplugged appliance, removed bottom cover, unscrewed 2 screws holding timer in place, unplugged timer and replaced with new part. Fastened back into place. Next removed back cover of freezer (5 screws using nut driver). Disconnected old thermostat and removed. Wires already had connectors installed. cut off the connectors with some wire left on and reconnected them to the new thermostat with the included blue wire crimps. Tried to use the shrink tube to insulate but couldn't get it snug enough. Just used electrical tape instead. Reinstalled thermostat. Reassembled cover. Plugged in and fridge and freezer are working fine again. Thanks partselect.com.

Not being sure which part it was, and having replaced the defrost timer already I changed all listed parts out. After 35 years they owed me nothing. I changed the control thermostat easily, I spliced in the defrost thermostat using the connectors and shrink wrap provided. The heater-defrosted element was a snap due to push/pull connectors.

Refrigerator is coopertone in color and matches the kitchen cabinets. oday the only viable option for a matching replacement is a subzero built in. Estimates for the cabinet work, subzero, electrician (to bring up to code) and plumber put the replacement at $12,000.

The unit is working like new with the replacement parts. I could have done more to isolate the faulty part but I think wholesale repacement was still a bargain.

I've fixed my Washing Machine and Drier with PartSelect parts and will continue to use them as my supplier.

Gregg
Massachusetts

removed back cover from freezer to replace defrost stat. removed cover from refrigerator to replace defrost timer

Make sure unplugged the frig before doing any repair. Just like other DIYers. opened up the evaporator located inside the freezer. Replaced the defrost thermostat, there's only 2 wires, so just make sure which is positive, which is negative. Replaced the defrost timer located on the bottom front of the frig. There's on 2 screws to unscrew. All those work took me less than half hour. Turn on the frig., now it works like a champ again. Hope it will last another 10 years.

First, I unplugged the appliance. Safety, first.
Than I removed the shield which was held in by screws. This covered the fan, thermometer.
The defrost thermostat was taken out, with a little extra force. The wires on the defective part were no longer attached to the part. The instructions were easy to follow in replacing the defrost thermostat. I stripped the coating on the wire, attached it with the enclosed electical bugs. The assy was able to follow, and the part went back on. The refrigerator is working perfectly. I couldn't have done it without the help in diagnosing the problem and with the speedy delivery of the new part. Thanks for all your help and the ease of the installing the new part!

I secured the power to the fridge. I took the metal panel which covers the cooling coils in the freezer off by removing the the 6 sheet metal screws. I used a standard hair dryer to melt the ice block which had formed due to the failure of the defrost timer. I replace the defrost timer, which was located behind the left front wheel of the unit. Finding the timer was the hardest part of the job. Since I was having trouble with the defrost cycle I also decided to replace the defrost thermostat due to its age. The most important item I would like to share is once all the work is done and the panel is back in the freezer, the power is restored take a straight slot screw driver and give the defrost timer about an eighth of a turn clockwise to ensure it starts. Then mark it with a sharpe and check it in 3 or 4 hours to make sure it is running. I did not do this on the one I installed and the freezer did not go into the defrost cycle. Once I got the timer started, well the ice cream stay frozen. BE SURE NOT TO WORK ON YOUR EQUIPMENT WITH IT PLUGGED INTO POWER SOURCE!!!

Jim