Actually, I suppose it's probably a short in the wiring of the actual stalk jack -- on a PCATS tuner this is an external jack, at the end of a small cable, right?
For reference, on a properly wired PCATs stalk cable, BLUE is pin-1.
Attachments
Description: PCATS stalk wiring, where it attaches to the PCB.
Description: PCATS construction notes for the stalk jack.