[sammyinthelbc]

I have a defrost problem with my refrigerator/freezer-coils won't defrost and refrig gets warm. I have read through many similar problems, and most say it's the defrost timer, defrost thermostat, or the defrost heater. That makes sense. Well, I changed the detfrost thermostat first, but it still didn't defrost. Then I tried the control board in back (because I don't have a manual defrost timer and the defrost heater test okay for continuity), but it still didn't defrost. Then, I knew it must be the defrost heater, so I replaced that, but it still didn't work! So, I have three new parts that should have corrected the problem, but it hasn't. I have checked all connections and I am still very confused as to what could be the problem. Any ideas would be greatly appreciated. Thanks

[richappy]

If you replaced the motherboard, I would replace the evaporator thermistor AP3185407 a small white item clipped to the top of the evaporator.

[denman]

GE's are a pain to repair as they like to keep everything a secret.

Here are your parts
Freezer section replacement parts for General Electric GSH25JSTASS Refrigerator | AppliancePartsPros.com

Here is a manual. Although not for your unit it may help to understand how GE does things.
http://appliancejunk.com/ge/refrigerator/31-9072.pdf

And here is a manual on their defrost system.
http://appliancejunk.com/ge/refrigerator/31-9062.pdf

All you have left is thee freezer thermistor Item 243 in Section 3 of the parts.

If that is OK then you may have a loose/broken wire between the control board and freezer and will have to check the continuity at the control board.

With a little luck someone else will jump in with the correct manual.
With a lot of luck perhaps the diagnostics in the manual I found will work.

[sammyinthelbc]

Thanks for the help. I'll review the manual and check the wires again. Then order the new thermistor if it checks out. I'm not sure how to check continuity at the control board.

[sammyinthelbc]

The Technical Service Guide seemed to work fairly well. I tried the self diagnosis procedure on page 33 - 36. First I did test 0 7, which tested the thermistors. The guide tests 5 thermistors, but when I did the test, it skipped 1 (maybe I don't have that thermistor in mine?). Anyway, 2, 3, and 4 all passed with a "P". 5 did not show a P, S, O, or B, rather it showed a symbol that looked like a 2, but it was missing the bottom part of the 2. So maybe that thermistor is bad??

I also did test 1 4, which tested the defrost according to the guide. I did the test, but the defrost heater did not come on. Would this normally come on in test mode even if I have a bad thermistor?

So, does it seem like I have a problem still with the defrost heater components and a thermistor? Any other tests I should try. Any help would be greatly appreciated.

Thanks

[denman]

5 did not show a P, S, O, or B, rather it showed a symbol that looked like a 2, but it was missing the bottom part of the 2. So maybe that thermistor is bad??
I do not know what was going on here.

I also did test 1 4, which tested the defrost according to the guide. I did the test, but the defrost heater did not come on. Would this normally come on in test mode even if I have a bad thermistor?
The way I read the info on Page 23 of the manual it looks like the thermistor does effect the test.

So, does it seem like I have a problem still with the defrost heater components and a thermistor? Any other tests I should try.
I would disconnect the heater/defrost thermostat at the control board and check them for continuity, should be around 20 ohms.
I would do the same thing with the thermistors using the chart for what reisitance value should be.

[sammyinthelbc]

Something was definitely different with the 5th thermistor test result. I'll try the continuity tests you mentioned, but it seems like the thermistor. Thanks for the help!

[sammyinthelbc]

It was the evaporator thermistor like you guys thought. After connecting, I ran the 1 4 defrost test and the heater lit up. Thanks guys, I really appreciate all your help!