Date: 201512
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Light Transport; Low Wing; 2 Turbojet Eng
Operator: Fractional
Operating under: Part 135
Mission: Passenger
Flight phase: Parked
Aircraft component: Emergency Exit Lighting
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Flight Cancelled / Delayed
Contributing factors: Aircraft; Incorrect / Not Installed / Unavailable Part
Primary problem: Incorrect / Not Installed / Unavailable Part

Narrative: When I went to test the Emergency Exit Lights; in the cabin at the Emergency Exit Door behind seat 2R; the two lights that illuminate the Emergency Exit handle did not illuminate. Taking note of this I went to look up the MEL for this item. In the process; I turned on the cabin Sidewall Lights that illuminate the lights in the cabin between the windows. Between every window in the cabin for the passengers; on the sidewall is a light that when selected; illuminates all the Sidewall Lights. Well; when I did this; the Emergency Exit Lights for the door behind Seat 2R illuminated. The side wall light that is located on the door; however; did not illuminate. I found this to be quite interesting as I had never seen this. I called into maintenance control and it was decided due to the wiring issue that the airplane would be left grounded and not to MEL the Emergency lights.However; when looking at the previous closed discrepancies; there was an entry from about 7 days earlier that stated the Transfer/X-Feed lever would freeze at altitude. The fix was that upon removing the Emergency Exit Door behind Seat 2R; moisture was found on the floor and cleaned out. Then the door was reinstalled and the discrepancy was signed off. It made me wonder if when the Emergency Exit Door was removed and then reinstalled that maybe the electrical plugs where incorrectly installed. It made me wonder if the electrical plug for the Emergency Exit Door Light and the Sidewall Light were the same type of plug allowing for this to happen. Also; it makes you wonder if the Emergency Exit Door is indeed removed; if an operational check is required of the Emergency Exit Light and Sidewall light. Also was the fact that this airplane had flown for a few legs and if indeed the electrical plugs were installed improperly; then crews did not catch this when checking the Emergency Exit Lights.Anytime the Emergency Exit Door behind Seat 2R is removed and then reinstalled; that the Emergency Exit Lights and Sidewall Lights are checked for functionality. Also; the electrical plug for these lights be of different type to prevent them from being installed improperly.




Synopsis: The two lights that illuminate the emergency exit handle behind seat 2R did not illuminate when tested. Emergency exit lights for the door behind seat 2R did illuminate when cabin sidewall lights were turned on.