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Parts for KitchenAid KSSS42FTX03 Refrigerator - AppliancePartsPros.com

See the attachments for some tech data.

[COLOR="Blue"]Is it possible that this model doesn't have one?[/COLOR]
Yes this unit does not use a defrost timer.
See the tech sheet on how to force a defrost cycle to see if the heater comes on.
Be careful to not burn your fingers on the heater.
Be sure that the defrost heater is frozen as it opens just above freezing killing power to the heater.

[COLOR="Blue"]
Is it possible that the freezer door was left open or something and so much frost built up that the auto defrost was not able to engage?[/COLOR]
No.
Defrost would still work though it may take a few defrost cycles to completely defrost the coils.

[COLOR="Blue"] I just can't figure out why it has been frozen over for almost a week and why sometimes I would find the freezer temp to be -9.[/COLOR]
Sounds like it may be a problem with the control board.
I would check the thermistors, see the tech sheet.
I do not think they have anything to do with defrost but I am not 100% sure of this.
If they check out OK then I would replace the control board.

The reasons I say this is.
-9 is too cold so there seems to be a problem with temperature regulation.
If you can force a defrost cycle then you know that the defrost thermostat and the defrost heater are OK therefore all that is left is the control board.

Below is a manual which may be useful to you.
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http://appliancejunk.com...&id=212;t=1409916004