John from Speartech said the wire he pulled from Pin 57 should work with a "Corvette TCM Tune". So I looked in the HPTuner repository for a 2011 Corvette tune and I updated the settings in "speedometer" to match (see attached Pic). I then tried to calibrate the speedo per the Dakota Digital instructions, but the speedo still wasn't seeing in pulses, :(. Just to verify the the DD VHX control box was working, I connected the speed sensor that came with the gauges to the VHX control box. I then used a cordless drill to spin it, and you could watch the pulses count up. There's definitely nothing wrong with the the gauges and I've done a continuity check on the wire that comes from Pin 57. So obviously it is something in the tune. I still need to track down a scope so I can see if the wire is putting out any signal at all and if so, is it the proper one....
