Fridge runs all the time

The fridge is cooling the items just fine but the fan is always running. It seems when I notice the fridge is always running. I have cleaned the coils and backside. I don’t want to call a repair person b/c the fridge is from 1991. What would cause this to happen?

Measure the back wall freezer temperature and post.

temp on back of freezer is 2deg F.

Turn the temperature knob all the way down and see if the unit goes off, then turn it back up unitl it comes on. Post what it does.

Nat

-On 11-19-08, I set the freezer control knob to it lowest setting and the fridge setting was at its initial setting that is stated by the control knobs.
-Some frost has formed on the items in the freezer.
-The refrigerator does not cycle on/off very often. It will run for over an hour before turning off.
-I measured the temp in the freezer to be -3deg F and the fridge to vary from 15-35deg F.

I am thinking that the thermostat or thermostat timer is bad.
What makes the refrigerator cycle on/off?

Here’s your parts breakdown Model MTX18GMBRAD
Sounds like the thermostat/control is going bad, part [COLOR=#0000ff]Control[/COLOR]

Nat

There is a defrost thermostat in the freezer box.
Might this be the part that I need to replace?

No, that is part of the defrost system. the part I listed above is the control.

Nat