Yes. These is supply, the return is at the bottom behind the crisper drawer.

Simon.

Here's an update from what I've learned:

Just pulled the rear freezer panel. It's full iced over at the bottom third of the coils, again.

Which is weird cause I know I saw the red glow of the defrost heater.

So I manually turned the rheostat control on the timer to begin the "compressor off / defrost cycle", and as it turned off, the defrost heater began to glow red.

But it only did it for a minute or so, then turned off way prematurely.

The defrost heater appears to work, but intermittently & not for a full length defrost cycle.

What could cause this ?

(Defrost timer is fairly new & does work as we hear compressor kick off every 6 hours or so.....)

Thanks for your input.

Sincerely, David :)