I am new to a 90 240 Dl sedan and new to this forum.

Tail lightsw, brake lights and dash lights do not work. PO had rear circuit boards (or what ever the tail light circuits are called) replaced and apparently they worked for a while.

I am searching this forum for help but am unfamilar with the forum tools and search and not having a lot of luck.

Any help, threads etc that you can point me to are greatly appreciated.

Does anyone have a reference site with wiring diagrams for the 240?

Thanks.

Suggest getting a Bentley repair manual. A cheaper option is a Haynes. I don't where there are any online 240 wiring diagrams, but I bet someone else might be able to help you.

Welcome to the Brickboard!

Your tail light and brake light problems may or may not be related.

Replacing the circuit boards was a good start. Here are some other possibilities. I had a 90 240DL sedan for 10 years and the tail lights were an on and off source of frustration...:)

1. Clean all tail light grounds and check all connectors for tightness. Clean off any corrosion you find. Check wiring as well.

2. Brake light switch is under the brake pedal. Check that it is operating correctly. Also check the third brake light wiring for integrity at its "box". They can go bad. I replaced the entire assembly (box) with one from a boneyard. Cured my brake lights out problem.

3. Under the steering column and slightly to the left (as I remember) you'll find a cylindrical relay about 3" long. Mine was red. It is called the "bulb out relay" and if it is bad you will have tail light and maybe brake light? issues. Expensive new. Find a used one if bad.

4. Dash lights are most likely bad bulbs or maybe a fuse. Check the fuses first in the fusebox. Is it the instrument panel lights or the console lights? If instrument panel you'll need to remove it. Replace both bulbs while you are in there. Takes about an hour tops. Since you'll be working around your steering column, disconnect your airbag first for safety's sake. As for the console, simply remove at least one side panel and check the various bulbs. I think there are at least three of them.

I agree with Jwalker's suggestions. I just had both of these problems on my 1992 240 wagon. First issue was to replace a couple of bad fuses in the fuse panel.

My brake pedal switch was bad and also the bulb failure warning relay. The pedal switch was kinda a pain, but a cheap $9 part.

I also installed some new console light bulbs to replace the burned out ones. All is working well now. Good luck.

13