A mechanic at the departure airport failed to address a loose wire to an emergency exit; suggesting the flight attendant have it checked at their destination. The flight attendant did not advise the flight crew until enroute.

Narrative

Departed uneventfully. Enroute to MCI a flight attendant calls up and said there is a wire hanging out below the wheelchair compartment door. She wasn't sure what it was; and could not tell me any specifics. I told her we would have it checked in MCI. After arrival; Maintenance took a look at it and told me it was the emergency exit light below the wheelchair compartment door. He told me that she had told Maintenance in our departing city and that our maintenance person told her to have them check it in another city.The flight attendant never mentioned it to me or the First Officer until we were halfway to MCI. Obviously; if I had known about the issue in our departing city; I would have had it repaired. This is a no-go item and the maintenance guy should have let me know about this. A logbook writeup was completed. Our maintenance did not have the part to fix it. We swapped aircraft and continued on to our next destination. If I don't know something is broken it can't be fixed. I'm surprised that any maintenance person would let something like this go unattended. Also; I think flight attendants should be a little more pro-active keeping myself and the First Officer in the loop.