I got the code from the dealer which includes two 5's but when I enter the code, nothing happens when I press the 5 button. I feel the click and all the other buttons work. Is there some other way to enter 5, or can the button be cleaned?

I would remove the radio first but you might try electrical contact cleaner right around the button, and working the button repeatedly while you spray.

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1983 380SL
1995 C280
1995 S500 coupe
1990 Mazda Miata
2004 Suzuki Hayabusa