Pretty much a show stopper unless you can test with a 24vdc power source. If you do test at 24vdc be sure to remember to recalculate the LED's resistor size for the higher voltage.Lefty
Back home after long day of coaching fencing ...Yep, 24V coil relay not going to turn on with 5V across it. Surprised it even clicks.
Try a relay like thishttp://www.dipmicro.com/store/842A-1C-S-5VDCeven get 10-20% discount on it if you can order now & be patient on delivery. (stock up a little - can get a ton of stuff for $20 with these guys).inexpensive shipping too, like $2.50 in the US.