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Replacement parts for Whirlpool GX5SHDXTQ00 REFRIGERATOR | AppliancePartsPros.com

See the attachment for the tech sheet.

You cannot find a timer because defrost is controlled from the control (jazz) board (Item 5 in Section 6).

First remove the evaporator cover in the freezer so you can see the coils.
Do not let them de-ice.
If they are heavily iced/frosted over you have a defrost problem.

If yes.
Manually force a defrost cycle, see the tech sheet.
When the fans and compressor turn off, you are in a defrost cycle.

Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the board needs replacing, re: it is probably stalling so is never getting into a defrost cycle.

If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item 10 in Section 8) from the wiring and measure it for continuity, usually around 20 ohms or so.

If the heater is OK
Remove one wire to the defrost thermostat (Item 14 in Section 8) and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.

I got desperate and called the repair man out, I had the cover off and the evap coil was covered in frost and ice. I took of picture for him and dethawed it before he got out. The heater measured 29 ohms which is good. I never did open the tech info sheet or I would have tried the service tests before I did the dethaw of the coil. All he did was the service test, never did open the freezer section to look or check anything and said I needed a defrost thermostat. He ordered one and the part should be in wednesday.