I just tested a MDC set for accuski part number was 6800-01001-00 . It would not drive any of our gauges. I recommend you clean all contacts, do not install speedo hoses, turn on power and see if each gauges energize by moving to zero. If they do then the MDC is ok and the gauges is too.
Or remove all gauges that dont work and the MDC and I can test to determine what works.
The next thing if the MDC is bad, then replace all gauges with Analogue gauges. If a gauge is bad, I have most of the gauges.
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Testing Send DECC and 2 button wth orange wire Rick Cohn 10200 Newington drive Orlando, Fl $75.00
Medallion wont respond to any request
Capt Rick