4×4 light came on

I bought the SUV listed above from a man who told me the four-wheel drive didn't work. When I bought it the light was on for the 4 by 4 and the two wheel drive was on also. Also the speedometer would not go past 20 miles an hour. After driving it for a week both of the lights went off in the speedometer started to work all at the same time. It's been 8 months since I bought it and today both lights came back on and the speedometer won't work. This is quite confusing I have no idea what it could be. Does any of this make sense? Have I been driving it all day in four-wheel drive? Thank you for any help you can give me.