Compressor fails to start sometimes?

I have a Whirlpool 6th sense side by side. randomly the compressor fails to start. Usually by disconnecting then reconnecting power it will work for several days then fail again. I have replaced the start capacitor and thermistor on the compressor. It still does the same thing. Now I noticed if the refrigerator door is open and I restart the unit by cycling the power the compressor will start but the inside light goes off but after I close and reopen the door the light seems to work fine. I am wandering if anyone knows which part or is it the mother board failing.