Have 16 yr old Kenmore

Question

Have 16 yr old Kenmore model 106.9537622. The heater strip at the center divider between freezer and frig gets real hot for a period of time everyday and causing frig and freezer to be too warm. The strip has a hot spot about half way between top and bottom.I was appliance repairman 30 years ago but could not find wiring diagram on frig and having trouble getting trim off to get at controls or strip heater.