Rear light problem

[JBell]

My Right rear light cluster has been dull for a week or so, time to investigate.

Opened it up to find this!!!!!





The plug has melted into the lamp holder, part of it snapped off (on the left) when I tried to remove it.

Thoughts on splicing a new plug onto the existing loom (and where to get one)????

 

[ZZZZ]

I have a couple of spare P21W sockets, can send you one

Two different types of plastic - finding a suitable glue / epoxy would be problematic, so you'd probably have to weld it in, short of replacing the entire holder.

 

[JBell]

I have a couple of spare P21W sockets, can send you one

Two different types of plastic - finding a suitable glue / epoxy would be problematic, so you'd probably have to weld it in, short of replacing the entire holder.

Thanks for the offer, I can buy the holder and a new plug with all the pins for around £30 so think this may be the best, fastest and easiest way to do it, I can rewire it myself fairly easily. Peace of mind as well

 

[ZZZZ]

You're right, it's the best way.
Also the P21W sockets are all over the place with mounting lugs, unlike say W5W that come in exact shape Mercedes use, so just clicks in.

 

[Ken_R]

That brown wire. I presume it is the Earth. I'd be checking the connection at the other end of it.

 

[Yugguy]

Classic W204 issue - earth wire is not thick enough so overheats. Some people have replaced the original wire with a better one.

 

[JBell]

That brown wire. I presume it is the Earth. I'd be checking the connection at the other end of it.

I will be , apparently it is a common problem according to Newcastle MB on the E-Bay listing for a replacement part

Classic W204 issue - earth wire is not thick enough so overheats. Some people have replaced the original wire with a better one.

Suggestions???? There is an earth point on the rear wheel arch so easy to re wire

 

[Yugguy]

Researching it it seems to be just a case of replacing the wire with thicker guage using the original endpoints. It seems to be done proactively - you might want to get a new cluster and do this before fitting it.

 

[JBell]

Researching it it seems to be just a case of replacing the wire with thicker guage using the original endpoints. It seems to be done proactively - you might want to get a new cluster and do this before fitting it.

I am going to replace the bulb holder and plug (just emailed Grangemouth for a price) so will use a thicker gage wire when I change it over, will have to trace the wire back but it is probably earthed under the rear fuse box.

 

[JBell]

Thanks YouTube

 

[umblecumbuz]

I had this with my C204 Estate, and found likewise - it is a common issue. Fortunately my burnt lampholder was salvageable so I ran two thicker wires and reused it. No more problems since.
Pain in the proverbial for a supposed quality car though.

Reflecting on my two current Mercs and previous iterations, and comparing them to the Panda, Suzuki and two Berlingos I also run, I am becoming more and more disillusioned with the marque.

 

[JBell]

I had this with my C204 Estate, and found likewise - it is a common issue. Fortunately my burnt lampholder was salvageable so I ran two thicker wires and reused it.

Where did you run them to??

 

[umblecumbuz]

Where did you run them to??

One was a more substantial earth - easy, to a chassis earthing point in the same location.
The other ... my memory fails me.
A gentleman in the next village has now bought the car, so I can't readily examine it.

 

[JBell]

One was a more substantial earth - easy, to a chassis earthing point in the same location.
The other ... my memory fails me.
A gentleman in the next village has now bought the car, so I can't readily examine it.

Cheers, I have ordered a new bulb holder, plug and 2 pins, it is going into my indy tomorrow for a coolant hose replacement so will pick them up then, it is the earth I want to enlarge and there is an earth point just under the fuse box right on the arch which will be easy to use

 

[JBell]

Plug when removed


All the warning lights came on while driving to the garage so had them do it

 

[ips24]

Has anyone got a how to guide to do this wiring please

Sent from my SM-G950F using Tapatalk

 

[Submariner1]

Plug when removed


All the warning lights came on while driving to the garage so had them do it


View attachment 41855

That looks like that got jolly hot.

Be interested to know what the cumulative amps are if one had rear fogs, reversing light, side lights and brakes on ... and what ampage that earth wire was?

 

[JBell]

and what ampage that earth wire was?

Not enough is the answer to that!!!

 

[Submariner1]

Not enough is the answer to that!!!

For sure, just looking at the photo it looks like 5A. I am surprised as MB is normally over engineered (or well I thought so).
Sounds like a really common problem.
At least it looks like, the heat damage was near the cluster and not buried somewhere bound up with a load of other wires.

My dear Mum bless her, had a C Class, and she probably would never have noticed something like that.
As she gave up driving when she was 92.

Imo that should have been a safety issue recall.

 

[L John]

Be interested to know what the cumulative amps are if one had rear fogs, reversing light, side lights and brakes on ... and what ampage that earth wire was?

Around 6 amps with everything on.
The wire should be fine but the connection has resistance and causes heat that runs up the wire. So the contact burs out and damages the last inch or so of the wire.

My dear Mum bless her, had a C Class, and she probably would never have noticed something like that.
As she gave up driving when she was 92.

Imo that should have been a safety issue recall.

It's just a burned out connector, the plastic used in these things don't catch on fire so it's not a safety issue, they just get very hot before failing and do localised damage, there's nothing close to it that can catch on fire by the heat.
It is a bad design though, I looked at mine when I bought it and it was fine. I'm going to have another look to see if it needs attention before it goes like the OP one has.