defrost timer went out, evaporator freezing up and not cooling

Opened the refrigerator door and slid the control to the off position. Removed food from the freezer area and took back panel off to expose the evaporator. Took a hair dryer and thawed ice until completely clean. Removed top panel from refrigerator and took a nut driver and removed the control assembly and lowered it enough to remove the defrost assembly. replced it with the new defrost assy. and then reassembled everything and turned the controls back to normal setting.