I have a GE Model #TBX18NI- 18.2cuft top freezer/refrigerator, and the freezer part is working great, but the refrigerator part seems to be getting warmer and warmer. I've tried adjusting the temp settings, but it hasn't helped. Someone mentioned something about a screen that may need to be cleaned of dust? Is that a possiblitly? Could you tell me where it's located if it is? Any other suggestions? I don't know how old the unit is, as it came with the house I bought last year. Thanks for any help! Tom Rizza

The frig has a defrost timer which activates an electric element which cyclially defrosts the evaporator in the freezer.If either the heating element or the defrost thermostat are faulty the freezer evaporator will freeze solid not allowing cold air circulation to the rest of the frig.
At a suiteable time empty fridge contents into insulated containers and turn fridge off at powerpoint and allow to fully defrost leaving doors open.The evaporator coil in frostfree is normally located behind the rear panel of the freezer.If you do not have defrost heater it will take 3-4 hrs for complete defrost.
After defrost turn fridge back on and make sure items to be returned to freezer are free from moisture and ice and keep freezer open for minimum of time as moisture will start building up onthe evapoator.
If the fridge works ok for a couple of days and the the original problem returns the problem is with defrost thermostat or defrost heater