The battery on my 2002 SLK320 was disconnected to clean the terminals. Now all I get on the radio display is WAIT. How can I get the stations back?

 

You need to enter the correct radio code following the instructions in the handbook.
Everytime you enter the incorrect code the time you have to wait before being able to enter a correct code goes up geometrically.

Afraid you will just have to wait.

Correct codes are available from MB subject to proof of ownership etc.

Stuart