Stem that controls lights on left side of steering column is malfunctioning. Dome light does not go out, except for one position that corresponds to darkest setting of panel lights. How do I repair or replace the control? Are there aftermarket replacement available?

 

No aftermarket on things like that. It's called a Multifunction switch. Try Ebay or a dealer. BTW, the dome light isn't supposed to Dim, the last setting turns it off