Here's the story...

My taillights were acting pretty strange for a while on the 92 240. With the car running, the running lights would come on fine. If I switched the headlights on, the running light on the drivers side tail would go out... press the brake the running light came on in place of the brake light and the passenger side running light would go off.

It was clearly screwy. I took it in to the shop last week and they agreed. They ended up switching the wires that go to the running lights with the brake lights. All seemed to work. It passed inspection that day (thursday).

Today I notice that both driver's side running lights front and back are out. Everything else works fine.

The bulb failure light isn't on either which is weird.

Another strange thing... when I got the car back on Thursday the gauge lights, which haven't worked in about a year, were suddenly working fine. I asked them about this. They said that they probably tightened a connection when they were down there adjusting the brake light switch at the pedal. (unrelated issue)

Any ideas? I just want my damn lights to work.

Thanks!

 

The lights on a 240 can be tempermental. Do you have a sedan? To me this problem is the result of using a flexible circuit board used on the sedan tail light assembly. The wagons seem to be a little better because it doesn't use the flex board. What can happen is that the flex board copper traces become damaged were the connector attaches, making the contact intermittent or not at all. If this turns out to be the case there are a few ways to solve it.

It can also be the way the bulb holder contacts the flex board as well. If you wiggle the buld holder and the bulb lights up, this could be the problem. I have tried cleaning both the metal tabs on the the bulb holder and the flex board copper with Scotch brite to get a better connection.

 

I use soft pink pencil erasers to clean electrical contacts, this removes the oxide without touching the metal coatings.

the best fix for funky old 240 tail lights is to get a new set and replace the whole assembly. makes the car look new again ditto headlights/parking lights.

but, your problem where turning on one light effects another sounds like a bad ground to me.

 

Thanks, guys. Sure enough, the fuse had blown for the left side parking lights. They all work.... for now.

 

any 240, you should replace ALL the fuses with the european brass/copper ones available on ebay and other places as 'mercedes w123/w124 fuses'. the tin ones corrode and develop failures that don't LOOK bad til you take them out and they fall apart. clean the spring contacts with a soft pink pencil eraser.

 

Are these the kind of fuses you are talking about?

MBCluster.com Mercedes W140 Instrument Cluster Repair Homepage

 

eggzaktly! pick a kit that has enough of all the right colors for car with plenty of spares. IIRC, the kit I got was enough for TWO cars. or, here... Volvo 30 Piece Fuse Kit for 240 & 260 AFTERMARKET 105869 3E1000 (one of my favorite volvo specific parts suppliers).