fridge not cold ...

I'm diagnosing a tenant's fridge problem. The lower compartment doesn't get cold at all, the freezer works like a charm. There's air coming out of the freezer's fan outlet, but nothing down below. We've defrosted, I've chipped ice away from the lower compartment's fan baffle, and I'm assuming at this point that I'll have to open the wall up to really clear out the ductwork.

Roper RT18DKXXL00 / 18ATR92

It's 12 years old, so not worth a great deal of repair expense. If clearing the duct fails, I'm thinking I need to test the frost-free components based on the advice at

Other symptoms are no dripping from the back drains, and one seems to be rusting up at the junction between metal and plastic. Could that be the ultimate cause?

Compressor and condenser seem OK from what I can tell, but then, I'm not

This is Turtle.

Yes Defrost terminator , Defrost Elements, and Defrost Timer are in line to look at.

Now you can have a defrost drain can stopped up and water will freeze in the air duct between the top and the bottom. This is something to look at as to drain stopped up and cause water to freeze up air channels under the freeze compartment floor. Totally defrost it and let it sit over nite and then clean out drain pipe going from freezer coil to pan under the units on right side.

TURTLE