GE Microwave/Oven Wall Combo Problem

I have model JKP86WF6WW which is called a GE Microwave Cooking Center. There is a microwave on top and on the bottom is an oven - it is all one unit.
When using the oven, I hear a clicking noise during the cooking process when the temperature is reached. I remember hearing it during the preheating process but never when it is actually cooking. Also, the area that shows the temperature is red and it is suddenly very difficult to read - the brightness is gone. Is this the start of something? Should I be concerned? Any help would be appreciated.