Disconnect the wire harness and set your multimeter to continuity or resistance mode
The 279973 kit includes both parts
WP12544002
DA47-00434ACM Refrigerator Defrost Heater
and R0606549
(2 Pack) XPIBE1740 Microwave Light Bulb (40W) Replaces 8206232A, WB25X10030 WP3387134 Disconnect the wire harness and2 Pack XPARTCO XPIBE1740 Microwave Light Bulb 40W Replaces 8206232A, WB25X10030 The XPARTCO XPIBE1740 is an aftermarket replacement 40 watt T8 appliance light bulb compatible with a wide range of microwaves, range hoods, refrigerators, ovens, and other kitchen appliances from GE, Whirlpool, KitchenAid, Maytag, Amana, LG, Frigidaire, Kenmore, Hotpoint, and more. It uses the standard E17 intermediate screw base found on most over the range and built in