Bench testing rally gauges

I'm not sure if it makes any difference, you have a rally setup(all 2nd gen cudas did), and the valiant one you are watching is more than likely a standard setup with an external plugin style ivr. Whether or not that makes a difference I dont know.
One of the other posts referred to a YouTube video for 69 Valiant instrument troubleshooting. Watched the video and it definitely seems like a power issue due to all the gauges looking like the power is removed and the gauges Slowly going dead and then recovering to there original positions or like they were powered back up. That is why I think the IVR is what I have an issue with.