Inside Cabin

Monitor not showing image of flags

First confirm if the monitor is turning on at all, do any lights come on or other indications that it is receiving power when turned on. If not then the first thing to check is the power cord in the back and where it plugs into an outlet. If you have any sort of remote outlet used as well double check it as well.
If not then its more likely to be a signal issue, first Check that HDMI cord is still attached behind monitor and that the TV is set to the correct input as well.

Check that HDMI and power is still attached to the BrightSign. To access the Brightsign, the entire dashboard of the boat will potentially need to come off or you may be able to access it by removing the switchboard panel. Some lucky stores can also get under it by unscrewing the front vertical panel of the boat dashboard.

Beyond the connections coming loose there isn't much left for you to check for this issue. You might need a new SD card for the Brightsign or other such issues that Tech Support can help you out with.

If they're connected and still not working, check that wiring is properly connected on the “flag” Arduino. You can check out the wiring for your Arduino in this article.
If the wiring on the Arduino is secure and it still does not work, contact Tech Support.

On the top side of the switches confirm that the bolts holding each toggle switch in place are comfortably tight.
Remove switch panel (see the previous section for how-to).
Check wiring in the back to ensure they’re all secure to the backs of each switch.
Half of the wires should run to the switches on the back and the other half go to a few different PCBs inside of the dashboard. Might be good to check these little PCBs as well to ensure the wiring is still connected there.

Check wiring on back of key switch (check previous how-to to remove panel)
If the wiring is secure and still doesn't work, you'll likely need to replace the key switch itself
If you've replaced the key switch and are having further issues, you will need to contact Tech Support

First diagnose if its not opening or not getting the signal to open. The latter means making sure your toggle switches and key switch all light up as they should and their wiring looks good as detailed above.
The former means triggering it and right when you turn that final key give a tug on the door to determine if its unlocked but just not springing open. In that case consider adding a small spring etc to push the door open when the maglock disengages.
If it doesn't stay closed at all then the maglock is probably not receiving any power. Do all the normal maglock checks and consider replacing it if all the connections seem secure.
You can check the wiring on the arduino side as seen in the arduino diagram.