daytrader152:
Hi dc42 and liudr,Thank you for your advice. Attached is a closeup of the Arduino with labels. It should clear up some confusion regarding the wiring.
You haven't yet implemented the suggestion in my reply #59 because the power and ground wires to the LCD do not follow the same route as the signal wires.
Keep the +5v and ground wires to the relay separate from the ones to the LCD as far as possible. You shouldn't need to use the same ground pin for both because you have 3 ground pins on the mega. If the LCD and relay share the +5V connection, keep that shared wire as short as possible.
How are you driving the relay: through a transistor?