I have an additional thermal probe being delivered on Monday, I'll see if jiggling the connector causes jumpy readings which would narrow it down to the cable. Connectors look clean so I suspect its a bad solder joint.
I BIAB, and the kettle probe is situated below the false bottom which works fine for heating strike water, but after mashing in, there is a considerable difference between what that probe reads and the actual temperature of the mash inside the bag. Up to now, I crank up the target temp several degrees to hit my target mash temp, measuring with a dial thermometer dropped through the lid, but its always a gamble depending on ambient temp and how much stirring I do.
The new sensor is 8" long, my plan is to drop it down through a hole in the lid while mashing, then switch back to the kettle probe during the boil.
On a side note, my probes and cables from the electric brewery all have three pins, those I see on amazon and elsewhere have 4 pins; which is the standard and is there a benefit of one over the other?
Edit: mailman just delivered the new probe, yay!