Dynon HDX & SL40 comm-help!

I am finishing up a panel update using Dynon equipment including the HDX, autopilot servos, adsb stuff, etc. Everything is working fine with the exception of the SL40. It isn?t communicating with the HDX. I have checked and rechecked my connections, rung out the wires, moved the serial ground to different places and tried a different set of serial wires from the HDX.
I?ve spoken with Garmin and Dynon about it and, while helpful, have yet to find an answer.
I will be looking for another SL40 to try but other than that, I?m out of ideas so if anyone has something for me to try, I?m all ears.

Thanks,

HDX and SL40

Steve,

Contact me at [email protected] so we can try a few things.

Brian