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Hey guys the other day I got a message " Active Headlamps Inoperable" and then "Check Right Low Beam"
I've checked all fuses and they are all good...high beam works still
Did you ever see fogging in your headlight? If so the moisture had destroyed your headlight control unit, see the thread I started on this very issue it's a well known issue with no fix available. I've tried everything I could with mercedes without any joy.
I've sealed the inside of both headlight control units to prevent moisture destroying the PCB. I now replace the desiccant gel packs every 6 months 45 mins work, I found a way to do it without taking the bumper or headlight off.
Dont let mercedes charge you to replace headlight assembly as they are very expensive and the issue will reoccur, dry out the headlight, replace the faulty control unit, seal them and replace the gel packs your self every 6 months.
All Cars Lost To Hurricane Isaac (W124 E420 revived - added 88 Allante 14 S550, 17 S63
Can you give us the link to your no headlight removal procedure for installing the gel packs
I am thinking of preventative as there is ever so slight misting in the right headlight... its about a half inch wide swatch across the inside top of the headlight... almost not noticeable but it is there after driving in rain...it dries completely in a couple hours when it does appear... for several years now.. no repair or fixes have been done to the light
Originally Posted by sclass350d
Did you ever see fogging in your headlight? If so the moisture had destroyed your headlight control unit, see the thread I started on this very issue it's a well known issue with no fix available. I've tried everything I could with mercedes without any joy.
I've sealed the inside of both headlight control units to prevent moisture destroying the PCB. I now replace the desiccant gel packs every 6 months 45 mins work, I found a way to do it without taking the bumper or headlight off.
Dont let mercedes charge you to replace headlight assembly as they are very expensive and the issue will reoccur, dry out the headlight, replace the faulty control unit, seal them and replace the gel packs your self every 6 months.
I have an s350d right hand drive here in Europe so the passenger side head light is very easy to install the desiccant gel packs as the upper control unit has easy access to the rear of the headlight assembly. 10 min job.
The driver side headlight is much more difficult as the windshield bottle is right behind the driver side control unit. But it's still possible to do it without taking the bumper off like Mercedes say they need to do.
Simplest way to do it step by step is to follow the WIS instructions for removing the windshield washer bottle, I'll link this below. Monday I'll update here with the parts numbers for the basket and gelpacks I have them on my work laptop.
Heres a brief overview of the steps from memory.
1) disconnect coolant reservoir electrical connect.
2) remove torx screw holding the coolant reservoir and gently lift it upwards moving the pipes aside as needed. But you dont need to disconnect any pipes.
3) remove all bolts holding the windshield shield washer bottle.
4) turn steering wheel on full lock to the right, you will see a retaining clip in the fender lining, remove this as it clips directly into the windshield washer bottle.
5) now gently lift the water bottle up and place it to one side you dont need to disconnect any pipes or electrical connection.
6) now disconnect the electrical connection to the headlight assembly. You will now have access to the 4 torx screws which hold the upper control unit in place. It is tight but it is possible to install the basket with the gel packs.
Just to note if you have a left hand drive sclass the steps should be same but just for the opposite headlights than mine.
Last edited by sclass350d; Feb 13, 2021 at 03:19 PM.
All Cars Lost To Hurricane Isaac (W124 E420 revived - added 88 Allante 14 S550, 17 S63
I thank you
And I have decided to speak for the community... “Thank you”
This makes a regular swap of gel feasible
many of the failures can be linked to failed gel packs due to not swapping them out...
Originally Posted by sclass350d
I have an s350d right hand drive here in Europe so the passenger side head light is very easy to install the desiccant gel packs as the upper control unit has easy access to the rear of the headlight assembly. 10 min job.
The driver side headlight is much more difficult as the windshield bottle is right behind the driver side control unit. But it's still possible to do it without taking the bumper off like Mercedes say they need to do.
Simplest way to do it step by step is to follow the WIS instructions for removing the windshield washer bottle, I'll link this below. Monday I'll update here with the parts numbers for the basket and gelpacks I have them on my work laptop.
Heres a brief overview of the steps from memory.
1) disconnect coolant reservoir electrical connect.
2) remove torx screw holding the coolant reservoir and gently lift it upwards moving the pipes aside as needed. But you dont need to disconnect any pipes.
3) remove all bolts holding the windshield shield washer bottle.
4) turn steering wheel on full lock to the right, you will see a retaining clip in the fender lining, remove this as it clips directly into the windshield washer bottle.
5) now gently lift the water bottle up and place it to one side you dont need to disconnect any pipes or electrical connection.
6) now disconnect the electrical connection to the headlight assembly. You will now have access to the 4 torx screws which hold the upper control unit in place. It is tight but it is possible to install the basket with the gel packs.
Just to note if you have a left hand drive sclass the steps should be same but just for the opposite headlights than mine.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
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Issue with right headlight 2015 S550
