Refrigerator experts; frost free problem?

[MariaAZ]

We bought a used Maytag side-by-side fridge last November. It worked fine with the exception that the temps in the freezer got down to -25 despite cranking the temp control all the way to the warmest setting. The fridge stayed at a steady 35.

A few months ago I noticed ice forming along the shelf just above the veggie crisper. Someone recommended changing the thermostat but situations arose that caused it to be put off.

About a month ago, temps in the fridge started edging up to a little over 40. Yesterday I discovered that the vents from the freezer to the fridge (one on the top and the other behind the veggie crisper drawer) were completely filled with frosty ice. Pulling off the back of the freezer compartment, the coil turned out covered in frost as well, plus a big chunk of ice right by the vent to the veggie crisper.

It occurred to me that when we first bought the fridge it would make this crackling sound for a few seconds duration, maybe as often as every hour or so. In researching the problem, I found reference that this could be the defroster kicking in. As time went by the clicking slowed down in frequency then stopped, and the fan started running for longer periods of time until it was going pretty much constantly.

I defrosted everything and plugged the appliance back in. The fridge is now down to about 35 and the freezer seems to be hovering between -5 & -10 for the past 4-5 hours. The clicking sound has returned, and the fan and compressor are back to cycling on and off.

This particular model has an "adaptive defrost board" rather than a defrost timer. I opened the door this morning and heard a buzzing/clicking sound coming from its general vicinity and shortly after the crackling behind the until started.

I'm not sure if any of this is normal fridge behavior and how to proceed if it's not. I'd like to try my hand at fixing it myself as it seems the problem is either the thermostat or (maybe even and) the defrost system which are all easily accessible. Any ideas would be greatly appreciated!

[dixieland]

Oursdid something like that. The noise was sounded like a fan blade hitting something, I lost everything in my freezer. I had a side by side. It was in the freezer part. Had to take everything out of freezer. Tale the panel out , it will show some thermostate on inside. Take it out.Need to find out brand of refregerator. I think it cost us $85.00 when the MAN fixed mine. Its making that same noise sorta.. Just keep watch on it.

[MariaAZ]

Yeah, that's what the crackling sounds like; a fan blade hitting something, but not as fast; only a few of those metallicy clicks and it's done. The fan itself works fine.

Our fridge has two thermostats actually... one for the temperature control and one for the defroster. I've got the part number for the temp control one but haven't ordered it yet. Right now I'm just happy that we didn't lose much food (what we lost was on the fridge side... things like milk spoiling more quickly but the freezer kept going) but I'd sure love to see if I can fix this thing and save the $$$ instead of buying a new one. Nice thing is, we were about ready to GET a new fridge but this defrosting might have bought me enough time to figure out if I can fix it or not.