Wiring new defrost heater for GE TFX22Z

check the heaters for ground leakage
have an electrician do the checks
moisture will trip rcd units as they work on a ground balance and milliamps will set them off so it could be moisture causing the problem
electricians have the equipment to check and find the cause

Replace thermistor on eveaporator. It's tube shaped, white with 2 white wires. it's held onto top of eveaporator with silver clip. You have to cut the wires and wire nut new one in. Evaporator is the set of coils that you mounted defrost heater to.
Also check defroster hi-limit on top of evaporator. It's the round silver unit. Try the thermistor first. Should be pretty cheap. The thermistor tells the board when the evaporator is warm enough. When it goes it won't defrost.

HI. There are two causes here, in this situation. The most common will be a faulty defrost timer, or adaptive defrost control board. The defrost mechanism will vary form unit to unit. Most newer units will be equipped with an defrost control board. This will be located in the control housing, just above the heat shield, in the upper right had side. Older models will have a standard defrost timer mechanism. If this device fails, the evaporator heater Assembly will not receive the command to defrost the coil, on time. The easiest way to isolate the cause, will be to test the heater element. If the element is functional, the defrost timer/board, will eb the culprit.

Defrost heater assembly test procedure:

The defrost heater is usually located at the back of a side by side freezer or under the floor of a top freezer. It will be necessary to remove obstructions such as the contents of the freezer, freezer shelves, ice-maker and the inside rear or bottom panel of the freezer, to access.

The panel may be held in place by retainer clips or screws. Remove the screws or depress the retainer clips with a small screwdriver. On some older top freezers it is necessary to remove the plastic molding to access the freezer floor. Removal of that molding can be tricky, so try not to force it, if possible. If you decide to remove it, you do so at your own risk. it will break, if forced. Warm it first with a warm towel, or hair dryer, set to low heat.

There are three primary types of defrost heater elements; exposed metal rod, metal rod covered with aluminum tape or a wire coil inside a glass tube. All three elements are tested in the same way.

The heater is connected by two wires. The wires are connected with slip on connectors. Firmly pull the connectors off of the terminals (do not pull on the wire). You may need to use a pair of needle-nose pliers to remove the connectors. Inspect the connectors and the terminals for corrosion. If the connectors are corroded they should be replaced.

Test the heating element for continuity using a multimeter. Set the multimeter to the ohms setting X1. Place a probe on each terminal. The multimeter should display a reading somewhere between zero and infinity. Because of the number of different elements we cannot tell what your reading should be, but we can be certain of what it shouldn't be. If the reading is zero or infinity the heating element is definitely faulty, and should be replaced.

Hi!

First of all you need to clean the coils (condenser coils under the unit or evaporator coils inside the freezer). The coils inside could be iced over because of failure of defrost system. Now check that the condenser fan under the fridge is working properly. Check that the fan in the freezer work which pulls cold air from the coils inside freezer and blows it to the fridge side. Are the temperature control knobs in the fridge adjusted correctly? It actually just opens a vent to let more or less cold air in from the freezer. It takes a while for the ice to build up in the freezer enough to affect the cooling.

My first guess would be the defrost timer. You can manually turn it to engage the defrost cycle and observe whether or not the defrost heaters come on. Now use a hair dryer to speed up melting the ice when there is lots of ice buildup. Most timers are 24 hour timers. It will turn the defroster on every 6 or maybe 12 hours depending on the model.

Before testing the defrost heater, unplug the refrigerator to avoid an electrical shock hazard.

The defrost heater is usually located at the back of a side by side freezer or under the floor of a top freezer. It will be necessary to remove obstructions such as the contents of the freezer, freezer shelves, icemaker and the inside rear or bottom panel of the freezer.

The heater is connected by two wires. The wires are connected with slip on connectors. Firmly pull the connectors off of the terminals (do not pull on the wire). You may need to use a pair of needle-nose pliers to remove the connectors. Inspect the connectors and the terminals for corrosion. If the connectors are corroded they should be replaced.

Please do rate this solution as FixYa and revert for further assistance.

Thanks
Rylee

This model does not have a defrost timer. It has a motherboard. You must jump out the plug to the main board to test the defrost circuit. In order to do this take the cover off of the main board, find the three wire connector on the base of the main board, connecter is normally blue in color. On the board itself it will identify termials as line, defrost, and compressor. To test you must create a jumper wire.Install the jumper in the plug terminals identified as line and defrost.This will turn the defrost heater on. If the heater does not come on, look for a defective heater or a defrost thermostat(mounted on the top of the evaporator). If the heater does come on replace the thermister(located on top of evap, white in color and has two white wires part#WR55x10025)

does the fan come on if not then the fan delay is bad

To force this unit into a defrost mode, unplug the fridge and remove the cover from the main control broad and remove the main wire harness. (Three wires, Black, Blue and Brown I believe) Next take a a small 3in wire and bend it into a U shape to make a jumper.


Insert the jumper into the main wire harness to jump the to outer wires together. (Black to Brown) It should be pretty easy to slip it in through the back with the rest of the wires. (Don't worry this test will not cause any harm to your fridge)
Now reapply the power to the fridge and check the defrost heater. As long as the defrost thermostat is below 15 degrees then the heater should start working. If the heater doesn't work then there is a problem with either the defrost thermostat or the heater. GE uses a glass tube heater with a coiled wire inside. This wire has a habit of breaking after a few years.

As far as the thermistors go, all the do is tell the board to cool. They can make the unit cool all the time but the board should still defrost the evaporator every 6-36 hours. If the unit starts defrosting then you have a bad board.

Hope this helps and let me know if you need any clarification. Good Luck!

The answer to your last question would be yes. You can test for voltage at the harness where you plugged in the new assembly. With the refrigerator defrost timer in the defrost mode do your voltage test. The thermo stat for the defrost does not close until the temperature drops to about 16°F. If you have and Ohm meter you can test for continuity through the heater assembly by testing heater end to end and bypassing the thermo disk. If you have voltage at the first point test where you connected the harness your timer is O.K.. If there is no voltage with timer in the defrost position it could be bad.

IT COULD BE A JUMPER FOR THE DEFROST BI-METAL OR A
WIRE USED FOR DIAGNOSTICS OF SOME KIND. IF THERE ISN'T ANYTHING AROUND TO PLUG IT INTO, I WOULDN'T BE CONCERNED. IF THE REFRIGERATOR DOESN'T OPERATE PROPERLY LATER ON, THAT MIGHT BE ONE PLACE I WOULD REVISIT.

It's usually the defrost heater on this model. Pull rear panel of freezer and remove the heater, (2 screws). It's at bottom of coils. Take to your parts place and they should be able to ohm out for you to see if it's ok. If it's all blackened, probably heater.
A check you can make is to pull refrigerator out to access back. UNPLUG UNIT!
Remove panel over control board on back of fridge. On the blue connector in bottom of board note the defrost terminal as specified on board. Unplug connector and put a jump wire from this terminal on the CONNECTOR, to the terminal that has the wire going to it with no wire next to it. Plug in refrigerator. If defrost heater is good, it should start glowing red within a few minutes. If it doesn't replace it.