The electric trunk latch solenoid can get stuck in the open position making it so the trunk will not latch closed. The diagnosing technician should verify correct electrical connection at the solenoid and check for correct cable routing. The trunk latch most commonly will need to be replaced.Google+
Car Problem Reports
Mercury Milan Trunk Will Not Latch Closed
Mercury Milan Problem
Average Mileage: 80,750 mi (32,000 mi - 123,000 mi)
Visitor, 2007 Mercury Milan, 95,000 mi
Trunk latch isn't working. I open the trunk with my remote and it pops open and makes a funny vibrating noise. I try to close the trunk and it doesn't latch.
Visitor, 2006 Mercury Milan, 100,000 mi
Mine has same problem!
Visitor, 2006 Mercury Milan, 90,000 mi
trunk wont latch and interior lights wont turn off