Brad does the bdi gauge work when the handset is not plugged in if so I would think the handset is bad but there is a way to test the handset and card on a bench you need a 24volt battery 2 car batterys in series will work you need to hook a wire to Pz plug number2 and to the battery negative terminal than you need to hook 1 wire to number 7 on Pz plug than to battery positive than hook handset to py plug hand set should power on.
I believe the py plug goes to the instrument panel l believe they only use 5wires you could ohm the wires from the connector to the dash see if there is any breaks if not it is possible that you have a bad card. l believe py1 is white to panel py2 isblack to panel py3 is green to panel py 4 bare to panel py5 red to panel l don't think that py6 and 7 are used some of the wirs are for pump to traction card. To check you have to take card out of truck. It would be better if you had a cheater pz plug to do it with. Hope l was of help