I have twin 700sci that came factory with a smart craft race view, junction box, and two mercury AGI boxes. I upgraded the dash to a mercury 403 which is a gateway box with a small screen, and two simrad 9s running off the nmea feed from the gateway. They all work perfectly.

when I swapped the dash out I had to unhook the two agi cables and the one output that feed the smart craft from the junction box. Very simple swap, however now I no longer have analog gauges and I have checked everything 4 times. The gauges power up and sweep, but the ones that have actual engine data are not working. My volt meters, gps. Water pressure work. My tachs temps and pressures do not. I called mercury for a diagnostic manual and they have no way to test the agi boxes?

anyone have a clue? Anyone know a way to test the input and output of the agi?