2009 Mercedes Benz GL tailgate open message on the dashboard

What is your question?

Sijo Cherian Hi, My 2009 Mercedes Benz GL tailgate open message on the dashboard even though its closed and when I put on drive all lights will turn on. When I try to close the door by pressing the switch, it closes the door,but looks like its not tight enough. I can hear the motor is running as for few more seconds. Could you suggest something please.

What makes this problem better or worse?

Its started just after a automatic car wash in shell

How long has your 2009 Mercedes-Benz GL320 had this problem?

4 days