In a LW4000 there would be heat tape in each rail (the end caps bolt on for access), each bridge rail (there is a square plate at each end of the rail for access), there should be a small piece of heat tape under each eye of the entrance eyes, exit eyes, and T-bar eyes. If the LW4000 has been upgraded to a Virtual Treadle, then there will also be heat tape under each VT eye and ultrasonic sensor. These heat tapes will be controlled by there own thermostat usually located in the VT's junction box. The other heat tapes require a temperature probe that runs from the JO to the bay. If the LW4000 is a docking dryer then there will also be heat tape around each magnet on the dryer bridge.