Try removing the batteries and reinstalling. Who knows, might work.
"Why do I get HHH or LLL for a temperature when I plug my probe into the unit?
99% of the time the probe is bad. If you have used the unit in the past the probe may have been melted, severely pinched or immersed in water. Any of these would cause the probe to short out and give a HHH, LLL or false temperature display.
If the probe is still under warranty please either call or email our customer service department with the model # of your unit and we’ll replace it free of charge.
If the probe is out of warranty please go to our parts and service section to obtain our order forms. You can email, mail, or fax the Probe Order Sheet to us along with your payment method and we’ll quickly send you a replacement probe."
Jim - Another transplanted Texan
Former KCBS CBJ
Large and Medium Big Green Eggs , Black 18.5" WSM, Blue Weber Performer - Stainless, Green Weber OTG Kettle , Brinkmann SnP Pro, and a Stainless UDS. One retired Portable Kitchen grill.
Red Thermapen, Maverick ET-732, EdgePro Apex Sharpener.
Avatar is the original 1951 Weber Kettle