h0rn3t920

So i posted once already on this but i really want to fix this.

My overhead map light in my car (the small reading light) does not work anymore. When i used to switch the bulbs, i would have to wiggle the whole assembly in just to get it to work. I figured something was just loose but thats not the case.

I used a multimeter and checked if the bulb was getting any power and it wasn't. I dont know why it isnt, but i want to fix the light so it works. All the other overhead lights work. Is there a fuse that is directly related to the reading light? Any help would be greatly appreciated.

h0rn3t920

if anything, can someone instruct me on how to safely take apart the whole dome light assembly? is that even possible without taking down the headliner? I really want to fix the light it drives me nuts when something isnt working properly in my car

raymond g-

if you have broadband, just download this 450mb file then burn to CD. this
file contains all the videos in the MB 210 technical CD which you see here.

if you dont have broadband, you should at least try to save select videos

RichardM98

Step 1 - Remove the two lenses (left and right). Since your car is old be prepared for the tabs to break off. Not your fault just old plastic.

Step 2 - Press back the two clips along the front edge.

Step 3 - Remove the lamp housing and disconnect the attached power cords.

For best results, do this with the key off. Then you can turn on the key to check voltage at each connection.

Your comment that it comes on when you wiggle it but nothing is loose is confusing. It sounds like you have a short or loose connection somewhere.

Good luck.

h0rn3t920

Thanks for that Richardm98! So I took the assembly apart. I disconnected a plug that I thought powered the reading light (Circled in red) and used a multimeter to see if any power was flowing to it and there isnt. I dont know why its not getting any power anymore but does anyone have any ideas? All the other lights work. I dont understand why the whole thing would just stop working.

And the box that I circled in blue, what is that? Is that a microphone? If so, I was thinking about removing it and placing my microphone from my Alpine HU into that slot. Sound like a good idea?

RichardM98

The image is pretty dark but I don't think that's a microphone. The microphone for hands-free telephone is a round (3/4") black 'knob' mounted to the headliner just to the left of the overhead light assembly.

Might be the in cabin temperature sensor.

You might try spraying a little electrical contact cleaner into the connector.

h0rn3t920

Well, i have switched the bulb out of the reading light quite a few times. And when used to switch out the bulb, i used to have to wiggle the bulb into the slot in order for it to work. I thought it was just faulty contact. If there was a fuse for it, i could see it being blown. But since there is no power coming from the connector, im confused. I will try that tho thanks Richard.

h0rn3t920

To be honest, I can't really see how the electrial contact in the connector could have gone bad if it's never been touched. I do see that this connector has 2 different sources flowing into it both coming from each side of the headliner. I don't know what these wires are coming from, but I just know that the overall connection isn't gettin any juice!

RichardM98

Well, you could check the fuses. Interior lighting is mostly on the panel under the rear seat. If you don't have a chart, they are posted over on benzworld. But I would be really surprised if each reading light bulb had it's own fuse which is why I haven't mentioned fuses before.

Giving it some more thought. There is probably only one power source to the switch. So check out the switch to see if you get power to the wires feeding the bulbs when the switch is on. If not , maybe replace the switch.

h0rn3t920

A wiring diagram for that dome light assembly would really come in handy right now.

h0rn3t920

I just cant figure out why no power is being sent to the map light circuit anymore. And Im pretty sure it stopped working when I switched a bulb out. It was a loose connection at the time but now there seems to be NO connection at all which is kinda strange. If anyone has any ideas, please let me know.

Hirnbeiss

Could it be CAN Bus related? Try disconnecting the battery neagtive terminal for 2 minutes then reconnecting to reset the CAN. Remeber to have your radio code handy.

raymond g-

noting that you've used the description "map light" and "small reading light" interchangeably,
prompts me to ask if they refer to the same light source, ie only the lamp on the passenger
side of the car is inoperative?

is there any correlation between door open (and if so,which one) vs light on or off?

the only consistent action in all this, so far, is that of the overhead lights (total of 3) only
the front passenger light is off?

does your model have front door courtesy lights beneath the storage compartment? do
they both come on when (each) the door is opened?

did you modify any of the dome lights to LED light source?

h0rn3t920

I am referring to the small reading light on the passenger side. The light does not illuminate at all, ever. I have switched the bulb back and forth from led before, and after while, the connection got loose. I'd have to wiggle it in and play with it in order for it to work. So when it stopped working, I figured It was jus a bad connection. But no power is flowing to that bulb anymore and I don't know why. All my dome lights are currently LED except for that one. I switched it back to the original halogen bulb and I can't get it to work either way.

h0rn3t920

So I reset the CAN bus and there has been no change to the light. Any other ideas would be greatly appreciated.

RichardM98

Have you tried pulling all the LED's and replacing them with the stock bulbs?

h0rn3t920

So I figured out that one of the 2 prongs that connect to the little map lamp light assembly, well only one of them is getting power and the other is getting nothing. I'm thinking of jus taking out the dome light assembly and soldering a wire to connect both prongs so they both will have power. Good idea or not?

h0rn3t920

Ok, very weird behavior from this light.

I figured out that the prong circled in blue is always getting constant power, the same amount all the lights receive when they are off. The one in red gets no power at all.

Now here is the weird part, when you switch on all overhead lights, the prong circled in blue sends power to the light, but the prong circled in red does nothing. I was thinking it acts as a ground but with the light installed, nothing. Doesn't even turn on.

However, if I use the grounding plate that is circled in black instead of the prong circled in red, the light will come on! BUT it only comes on when you turn on all the overhead lights. It will not come on if you just switch on the map light.

Idk why the light is acting like this, but im willing to buy a whole new dome light assembly if i have to. But i want to iron down the problem to the switch before i go ahead and buy a whole new assembly. Can anyone offer an input? thanks.

h0rn3t920

any help here? would be greatly appreciated.

BBriBro

I'm having the same problem on a '97 E300D. It worked just fine and now nothing. No power to the little map light at all. Your idea of running jumpers to the dome light would get it to work with the dome lights, but you wouldn't have separate control via the map light switch, you would always have to turn on all the lights. Did you buy a new overhead console? I've checked fuses, disconnected the battery. There is obviously power to the overhead console since the other lights work, I'm hoping it's something within the console itself.