Why the daytime lights auto door locks and speedometer do not work on a 1990 Dodge Dynasty?

Okay, I'm not a mechanic by any means, but I have had the same problem. As far as the auto door locks go, check your fuses. The auto door locks are on the same fuse as the lighter and horn. I went to use my lighter one day, and it blew the fuse. My door locks, horn, and lighter would not work. I didn't know this until after I replaced the fuse several times (and finally hearing a popping sound when I went to use the lighter).

As far as the daytime running lights go, I really have no advice. There are a few others who have asked the same question here... Just browse through the questions and you should find the answer.

The speedometer may be a bit tricky. Either the gage itself is bad, or you may have problems behind the dash... Again, others have asked a similar question, so just browse through the questions and you should find an answer.

Sorry I couldn't be more help.