Freezer works. Defrost does not work.

Photo shows ice build-up just 7 days after using hair dryer to defrost.

The heater coil reads 25 ohms, so it probably works. Need to find the timer in order to continue diagnostics.

A. Where is the timer? Is it perhaps behind the controls cover in the fridge section?

B. Must icemaker cable be plugged into icemaker unit in order for the defrost system to function?

1. Thermostat
2. Icemaker cable placed out of the way. There is no water source at this location so icemaker has been removed.

Seeking your advice. Thank you!

Phil M