A little help

[jbadgio]

I just purchased a 1990 190E 2.6 and could use a little help. The central door lock system does not work. If either of the front doors is unlocked or locked, the remainding doors will not unlock or lock. What do I need to look for here? Also, the bulb must be burned out where the shifter is; it is hard to detect P N R D etc at night . How would I go about replacing this bulb; especially since I do not know where it is located? One last minor thing, the trip odometer does not retreat to "0000"; it kind of gets stuck. Any suggestions here?

thanks,

John