I have a 1993 400SEL, which I recently purchased; however, the radio does not come on. When I cut the radio on, the word, "WAIT", flashes. (According to the manual and the dealer, the word, "CODE" is supposed to appear at which point in time I would punch in the code - which I got from the dealer.) The problem is that the word, "CODE", never appears. I have left the car running for 30 minutes to see if the word, "WAIT", ever shifts to "CODE". It does not happen. Anyone have the solution?