High i have a Hot Point refrigerator (hts22gbpbrww) the coils in the freezer get solid ice and the flow of cool air does not get to may fridge because it looks like the passage is iced over. I gotta take my heat gun and melt all the ice off the coils and out of the drain and it works for a while and the same issue comes back. The time it works is getting less and less. Is it likley to be the glass defroster or a sensor?? or something else???Thanks

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Replacement parts for GE HTS22GBPBRWW | AppliancePartsPros.com

The defrost timer is Item 257 in the Fresh food section.
There is usually a hole in the cover so you can get to the cam.

Remove the cover from your evaporator coils so you can see the heater.
Then using a screw driver turn the cam on the defrost timer till the compressor, compressor fan and evaporator fan shut off.
Note: the cam only turns in one direction.
You are now in a defrost cycle.
Note: the defrost thermostat must be frozen as it turns power to the heater off just above freezing.
If the heater heats up then the defrost timer requires replacement.
Be careful, do not burn your fingers.

If it does not heat up it is either the defrost heater, thermostat or the contacts in the timer.
Easiest way to check is with a meter.
Defrost thermostat should be 0 ohms when frozen.
Note: I do not know why they have two defrost thermostats in this unit and have no way of getting a wiring diagram. Take a look behind the kick plate for the wiring diagram this may answer this question for you.
Perhaps someone else knows the answer to this.
Sometimes you can see if the thermostat is shot as the case is bulged out
Defrost heater is usually around 15 ohms.
Looks like the heater is a glass type so you may actually see where it is burned out. They do have poor reliability compared to the Calrod type.
If both the above are OK then by default it is the timer.

Here is a good site with additional info.
http://www.applianceaid.com/refrigerator.html