I have a Maytag refrigerator MTB1504ARW. Could anyone be so kind to explain me how I can remove the sheet metal panel inside of the freezer section to check the coils for ice buildup? I have tried this but the panel doesn't come off easily so I am worried not to brake something. Cheers!

Very easy, since you have no light in the freezer. First, you should know that if you can't see any frost on the surface of the panel, you may not have any problems with frost occlusion. Can you hear the fan running? To take the panel out, first remove all food and the shelf from the freezer. Then remove the ice maker fill tube plug at the upper left corner (it simply pulls out at a slight downward angle). Then remove the two 1/4" screws on the left and right sides of the panel. You will then pull out at the top of the panel. Don't pull on the bottom because the fresh food air duct on the front of the panel has a lip that goes into a hole at the bottom. Once the top is clear, you can lift and swing the panel to the left to view the evaporator coil. If you have any questions about what you see, let me know.

You should be able to remove a plastic panel, not sheet metal, by removing screws that hold it in on the front bottom of the freezer. The panel then slides out and you then may carefully lift a Styrofoam sheet up to see coils and defrost heater. Only after you remove the bottom piece can you remove the back piece with the fan. Don't remove any sheet metal! You will surely break something then. DrTom4444