That crack shouldn't make a difference. The wire that powers the dash comes off the same post as the battery cable on the starter. If memory serves, that wire goes to the amp gauge, and everything else gets power by being on the same terminal post. The fuses could be bad for lights and dash, but ignition is not fused, so it should work, unless there is a bad connection. A wire could have broke off at the connector. Since nothing works, I think you problem is going to be at the amp gauge. If it was the key switch, the lights would still work.  A multi meter would be a good way to check and see if you have 12 volts at the post on the amp gauge with all the wires on it. If none are broken, then take the nut off the post (disconnect the battery first) and clean up the wire ends, and then put it back together.