sounds like it could be inside the gauge - the very fine wires from the activating coils might have broke or come loose and sometimes makes contact, like when air temp or humidity is just right - I'd try a different gauge if you can find another

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics