I have a 4 year old GE side by side refrigerator. The evaporator coils
freeze-up about once a month. We have to un-plug the 'fridge and let the
coils thaw out for the unit tro run properly.

One other symptom, one of the two light bulbs (the upper one) in the
refrigator side of the unit will not work. A new bulb will not work, the
switch is good, the second bulb works.

I have a basic understanding of the system. I thawed out the coils two days
ago and vacuumed out the area under the 'frige, behind the bottom grill.
Where do I start the troubleshooting?

Thanx

Frank