2016 C300 W205) Weird Headlight Issues
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Newbie
Joined: Aug 2023
Posts: 4
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From: Central Illinois
2016 C300 4Matic
2016 C300 W205) Weird Headlight Issues
2016 C300 W205
The drivers side front lights are doing weird things. The low beam is intermittent. The daytime running light is not working at all. The turn signal bar is always on when running. Even for a minute or 2 after shutting off the car. It will even come back on without the car running. The turn signal doesn't blink when activated.
There is A LOT of moisture inside the entire unit. Is this the cause of the problem? Do I need to replace the entire assembly?
Thank you.
The drivers side front lights are doing weird things. The low beam is intermittent. The daytime running light is not working at all. The turn signal bar is always on when running. Even for a minute or 2 after shutting off the car. It will even come back on without the car running. The turn signal doesn't blink when activated.
There is A LOT of moisture inside the entire unit. Is this the cause of the problem? Do I need to replace the entire assembly?
Thank you.
Out Of Control!!
Joined: Apr 2019
Posts: 12,002
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
HL killer... humidity
2016 C300 W205
The drivers side front lights are doing weird things. The low beam is intermittent. The daytime running light is not working at all. The turn signal bar is always on when running. Even for a minute or 2 after shutting off the car. It will even come back on without the car running. The turn signal doesn't blink when activated.
There is A LOT of moisture inside the entire unit.
Is this the cause of the problem?
Do I need to replace the entire assembly?
Thank you.
The drivers side front lights are doing weird things. The low beam is intermittent. The daytime running light is not working at all. The turn signal bar is always on when running. Even for a minute or 2 after shutting off the car. It will even come back on without the car running. The turn signal doesn't blink when activated.
There is A LOT of moisture inside the entire unit.
Is this the cause of the problem?
Do I need to replace the entire assembly?
Thank you.
Heavy moisture condensation puddled insde the HL at the lowest point where the unprotected electronic module is conveniently located. The unit is powered directly 24/7. It is remotely managed by SAM
These units need to be coded by a MB specialist. You may be able to rescue the HL and replace only the controller module. Good luck figuring options & part numbers.
Its hard to say how long this repair will last because the root cause is with the defective venting system. It brings in moisture that accumulates into water.
It does not need heavy rain... I've seen this happen with coastal fog as well.
++++ Fix analysis ...
The HL factory defect is caused by internally regulated TEMP being set too low. This causes dew condensation to accumulate water.
Temp needs to be reprogrammed else more destructive condensation will occur. (Remember that repairs are covered by shop warranty).
Last edited by CaliBenzDriver; Nov 11, 2023 at 10:10 PM. Reason: Lin
Thread Starter
Newbie
Joined: Aug 2023
Posts: 4
Likes: 4
From: Central Illinois
2016 C300 4Matic
Good job, you are 100% correct!
Heavy moisture condensation puddled insde the HL at the lowest point where the unprotected electronic module is conveniently located. The unit is powered directly 24/7. It is remotely managed by SAM CANBus.
These units need to be coded by a MB specialist. You may be able to rescue the HL and replace only the controller module. Good luck figuring options & part numbers.
Its hard to say how long this repair will last because the root cause is with the defective venting system. It brings in moisture that accumulates into water.
It does not need heavy rain... I've seen this happen with coastal fog as well.
Heavy moisture condensation puddled insde the HL at the lowest point where the unprotected electronic module is conveniently located. The unit is powered directly 24/7. It is remotely managed by SAM CANBus.
These units need to be coded by a MB specialist. You may be able to rescue the HL and replace only the controller module. Good luck figuring options & part numbers.
Its hard to say how long this repair will last because the root cause is with the defective venting system. It brings in moisture that accumulates into water.
It does not need heavy rain... I've seen this happen with coastal fog as well.
Sounds wonderful.
Can the venting system be modified to fix the defect? Is there an updated replacement assembly that takes care of the problem?
Newbie
Joined: Nov 2023
Posts: 4
Likes: 1
C205 W/ M177
The fix would be to replace the headlight and all modules connected to the headlight (you must replace everything since you're dealing with water contamination). Then you would book an appointment with an MB dealership to have it programmed. The theory is that your headlight is just a plastic box with LEDs and wires. The headlight modules control all the options, commands, and procedures related to lighting.
Last edited by MB_Carti; Nov 11, 2023 at 05:33 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 12,002
Likes: 6,827
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
fish tanks
You can try to deal with venting to control moisture penetration. Some venting is necessary to cool internal heat.
The current solution collects moisture until swampy electronic shorts out to drain batteries.
