W211 Courtesy light problem
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Junior Member
Joined: Dec 2013
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From: Garden Grove
2003 E500 Sport and 2004 E55 AMG
W211 Courtesy light problem
Today I replaced my interior lights with led's and everything's working fine except the courtesy lights. I began with the driver's side and the led worked fine. I than moved onto the passenger side and installed the led. It did not work even if I flipped the bulb around. I then went back to the drivers side to see if it was still working, and it stopped working. So I put the led bulb back into the passenger side and it worked. Now my driver's side courtesy light does not work with both the stock bulb and led. does anyone know what the problem might be?
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Joined: Nov 2013
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From: I live in San Diego County.
95 W124 E320, 104.992 3.2L 6 Straight
Don't know much about the 211's
As above, however if MB continued to do the same as with previous models, there might be a relay i.e. some control relay behind the instrument cluster, don't quote me on the location.
If so, chances are that the control/relay burned a trace and a diode inside the module.
The diode prevents current to flow back through the other doors contact, sort of an OR gate. If the diode is defective, only one side triggers the courtesy light. Either the relay may have to be replaced, if you can find it, or once you found it you may be able to test/replace the diode and possibly bridge the burned trace, IF THIS IS THE SOURCE OF THE PROBLEM....
If so, chances are that the control/relay burned a trace and a diode inside the module.
Why? Perhaps a contact, spade connector is not completely isolated from ground, and touched part of the metal frame where it shouldn't.
Junior Member
Joined: Nov 2013
Posts: 16
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From: I live in San Diego County.
95 W124 E320, 104.992 3.2L 6 Straight
Forget above post
After one more cup of coffee, I finally woke up.
This is a different scenario then I visualized!
First of all I would get myself new light bulbs according to Manuf Specs and insert them.
Check if you can get it to work correctly again.
If so, then my best guess is that the LED's don't draw enough current.
Everything nowadays is computer controlled or switched on and off.
The computer / control module may not see enough current to switch properly.
In the course of checking, swapping etc. your old bulb may have seen the dark end of the tunnel and doesn't want to come back any-more.
That's why I said to get a new one and try to get back to original state.
If it works again, then try the LED's again.
Many times the LED manufacturer forget to tell that LED's draw a lot less current and actually may trigger some fault in dash e.g. burned out bulb. The dome light is, I think, not in the loop, but may still be controlled by some module that doesn't switch.
Sorry about the above comment, that may not apply entirely to your problem.
This is a different scenario then I visualized!
First of all I would get myself new light bulbs according to Manuf Specs and insert them.
Check if you can get it to work correctly again.
If so, then my best guess is that the LED's don't draw enough current.
Everything nowadays is computer controlled or switched on and off.
The computer / control module may not see enough current to switch properly.
In the course of checking, swapping etc. your old bulb may have seen the dark end of the tunnel and doesn't want to come back any-more.
That's why I said to get a new one and try to get back to original state.
If it works again, then try the LED's again.
Many times the LED manufacturer forget to tell that LED's draw a lot less current and actually may trigger some fault in dash e.g. burned out bulb. The dome light is, I think, not in the loop, but may still be controlled by some module that doesn't switch.
Sorry about the above comment, that may not apply entirely to your problem.
Junior Member
Joined: Nov 2013
Posts: 16
Likes: 0
From: I live in San Diego County.
95 W124 E320, 104.992 3.2L 6 Straight
