I have a 2005 C230 sedan. The previous owner changed a few lights out going for the LED look. I was getting constant messages saying lights were out and my lights would act weird at times. I decided to put everything back to stock since the look wasnt worth the trouble I was having. After removing LED bulbs from the front corner lights and license plate lights I got the messages and light issues down to just my tail lights. The previous owner changed the tail light assemblies to ones that have LEDs for the top. The message I keep getting now is back up lamp is on (it's not) and left turn signal is out (its not). I ordered two new housing for the tail light bulbs and put them in thinking that might fix it, it did not. I verified that the correct watt bulb is in each slot. I have removed the housing from the tail light assembly so that I can plug in the correct 21w bulb instead of the LED one.

The problem is that the bottom two bulbs on each side never come on. When I have the car running and switch the lights from on, to auto to parking lights the only light that stays on constantly is the top bulb. The turn signals work fine and the brake light works fine, to include the third brake light in the trunk. If I have the lights on only the top bulb on each side is lit up, when I unplug the right side assembly nothing changes on the left side assembly, when I plug it back in the bottom bulbs come on for a split second then the top bulb is the only bulb on again. When I unplug the left side however the right side top bulb goes out and the two bottom bulbs come on.

I dont have a service manual for the car yet so I am at a loss what might be in the left hand circuit that could be causing my problem. I use to work on helicopters and airplanes so I am not completely lost working on my car but without a schematic Im just trying to solve the easy problems right now.

I am open to any and all suggestions and help I can get.

 

That doesn't seem right at all. the top light (red) is the brake light. The bottom ones (also red) are the ones that go on when the car is on and it's dark outside.

With that said, I thought I read somewhere once that the brake light does the job of the bottom bulbs if the car thinks the bottom bulbs are out. The split-second "flash" you're seeing is probably your car turning on the bottom bulb, deciding the bulb is out, and then resorting to the "backup mode" where it substitutes your brake bulb instead.

Assuming the previous owner didn't hack up his electrical system, I would try replacing the bottom bulbs first. MB cars are sometimes a bit too smart for their own good - they'll think a bulb is out when the resistance (or whatever they're measuring) goes outside a predetermined range. For example, I often solved a "turn signal out" error in the rear by simply swapping the bulbs between L and R sides (both bulbs were not burned out). Another (dumb) reason for these errors can be dirty bulb contacts. I once had a constant "bulb out" error, and solved it when I looked inside the connector and found a blob of grease (possibly left by someone at the dealership) on one terminal, and wiped it down.

Good luck.

 

I replaced all of the bulbs when I ordered the new tail light assemblies to make sure that wasn't it. I have switched them from side to side to make sure it wasn't specific to a bulb.

The wiring looks good, when he did change out the bulbs for LED it looked to me like he did it the correct way with resistors and all so I don't think he cut into the wire anywhere. I will look at the wiring though, the backup mode thing you are talking about makes perfect sense.

 

any updates i have the same problem

 

To properly diagnose you need diagnostic tools . You may need to check the coding of the sam too. The sam needs to "see" loading on the circuit before it will output and drive the lamps. What u seeing happen is lamp substitution. The Sam detects an error in any tail lamp circuit and switches to stop lamp circuit with lower output current as a substitute .
You need to read fault memory and work from there

 

there is no code the lower outers go brite after turning on light not dim like they should

 

Did you do actuation to test each circuit? What diagnostics are u using

 

These cars suffer from bad tail light grounds. I use to get the brake lamp out message on the dash when they were fine.
Remove the ground wires. Sand, wire brush etc.
Worked for me. There is a video on youtube showing the installation of a Mercedes fix "kit" for this very problem.

Good luck, Dave

 

Where is this ground located. I have to get inspection and this is driving me nuts

 

The pigtails in the rear have a resisitor in them. Mine failed, burned out..
I replaced it.
When it gets wet outside I it uses the backup lights.
I've tried everything. Bulbss, cleaning contacts, swapping harnesses, I most recently replaced the seals in the tail lights.
I actually dont drive it anymore in rain, so not yet sure if it helped. Trunk light sometimes blinks 3 time pause and repeat.
Some sort of code. I don;t know what the helll it means.
Possessed.

 

I had a message for left brake light… new bulbs it was fixed for 1 day. Message came back, but they are working. With only a slight delay between left and right brake…. What’s going on!? I’ve heard Benz is picky w brand of Bulbs, I’m using a 7528 but apparently I need I better name… Really?!