Without a meter to test,Carefully check to see if the compressor is hot.( if it's hot may need relay or compressor ) If not turn the small round "dial" on the control to the left of the compressor clockwise about 1/4 of an inch. If it starts, bad defrost timer. If still no luck the temperature control may be bad. Hit the knob on the control with a wooden spoon, if it starts bad control.Hope that helps.