New thermometer and probe time

No matter which you buy, look on the package BEFORE you throw it away, and check the temperature rating of the probe wires.  Thats the biggest problem area.  The highest i have seen is 450 degrees.  Now consider that area of your egg that "open" directly exposed to the glowing lump below between the feet of the plate setter.  If you are cooking with a dome temperature of 375 degrees, the temperature in this exposed area is well above 500 degrees!!  Keep a couple of layers of foil wrapped around the first 12 to 18 inches of probe wire to protect this area of the probe cable..

Ditto above. Alway good to have your thermopen as a backup. Do you just need a replacement probe? It is common for them to get worn out due to high heat cooks or from linking the cable when handling. Just a couple things to watch out for next time around. Thermoworks products are pricey, but to of the heap in quality. BGE makes one, not sure who manufactures it for them, it could be a maverick in a BGE package.

@nolaegghead suggested a fix if water intrusion was what caused it to quit in Thermometers I use a DigiQ which is a expensive solution but I just wanted to pass along his advice to see if it could help you out.