hi, I recently bought a '90 240DL sedan which has brake light and tail light issues. Both R & L brake lights do not work, however the middle 3rd brake light does ; and the L tail light is not working while the R tail light does. Advice where to start theinvestigative workwould be greatly appreciated. Thank You in advance !

 

This was a chronic issue on my 240s and had to do with the connections between the clip on wiring harness and the PC board in the tail light assembly. (usually the drivers side light) I'd go the easy way first and check the harness is OK with a meter or test light, then proceed to cleaning the connections and grounds.

 

Pull off the taillight housings on both sides. Check all wiring and connections and grounds for corrosion or loose connections (I recommend pulling each wire and putting a dab of de-ox on each one). Change all the bulbs and check to make sure each bulb contact is good (more de-ox). I do all of mine yearly (93 240 wagon) just to prevent problems. De-ox is available at any auto parts store. That's the way to start, the only cost is the bulbs and a little time.

 

As strange as this may sound-make sure that he tail light assemblies match. There are 2 options for tail lights on the sedans-chrome or black. the difference is seen when you look at the line between the 2 rows of lenses. Not sure if that's any new info for you ,but good luck! Also, I would check to be sure that the circuit panels (that the sockets make contact with) are in good shape-no corrosion

 

Check behind the dash and sometimes the connection isnt vewry good on 240's and if that not it then take off the covering in the backa and start following and tasting wires.