paquettc

Hi,

Recently, I was getting an intermittent rear left turn signal error on my 2009 ML320. When I was on vacation it went out permanently (although it did work for a short period of time after a rain storm).

I've spoken with Mercedes and they've changed the part number of the tail light assembly and there's a new gasket seal. Apparently this is a known problem with water getting in and messing up the led pcb boards.

So, I've had the tail light assembly out in an attempt to try and clean any corrosion on the boards that could be causing the failure. Only 2 boards are partially visible. Short of just pouring RA in the assembly and letting it dry out, does anyone know if it's possible to get at the boards inside the assembly?

Thanks,

Chad

Tasopappas1

Had the same issue o the the wife's 550 and had my independent mercedes guy work on it. He advised there is no way to get at the boards as the unit is completely sealed.
Had to buy a replacement tail light.

thomas1234

Hi Chad,
I have recently had same/similiar problem with right side tail light in the signal portion of the assembly- the 2 adjacent leds on left side of the upper row of 4 leds do not work at all. Remaining 2 leds on upper row plus the lower row of 4 leds "work" albeit very faintly. Other than that the rest of the assembly works!
I have assembly dismantled- it is not sealed- it does not require cutting with a dremel. Heat with a blow dryer the edge of assembly-gently pull off lens while heating at same time. Start pulling lens apart at "tapered" end first. Lens "sealed" on to assembly with silicon but mine came apart easily- silicon dry/old and hence possible reason for issues. At back of assembly- a total of 5 small screws need to be removed to access pcbs - 2 at top, 2 at bottom, and there is 1 hiding under the foam where bolt is at "tapered" end. This gives access to the pcbs- a total of 4 pcbs. The pcbs are held on by a total of 10 smaller screws. LED lights are surface mounted to the pcbs.

This is where I am stalled. Help if it is out there!?
I did solder a 10amp copper wire ground to metal part of light assembly as poor grounding is frequently noted in forums as a problem. This did not fix my signal problem. The leds are surface mounted and appear to be of a plastic weld/solder and I have not been able to locate the same type of leds on line.

I have not given up- but definitely at a full stop. It is possible to trouble shoot the pcbs but I need to read up on that.

Trying to avoid having to purchase a brand new assembly for appox $300-$500.

Thomas

khelms_98

Add me to the list of owners experiencing the same issues. Driver's side turn signal has gone out completely and throws a code everytime, plus a few taillight LEDs are out. Passenger side turn signal works fine but taillight LEDs are out as well.

Dealer says a leak on the driver's side caused its malfunction, indicated by rust on a bolt near the light assembly. I've read about very similar issues on other forums so we're certainly not the only ones.

OUZO Power

Add me to this. We just had a heavy downpour overnight and when I went to unlock the car this morning I got the message.

Passenger side LED rear Turn flickers and barely lights up.

Do I need a new tail light?

OUZO Power

It was my tail light. Had to be completely replaced. Works. And MB gave me a 20% discount.

I haven't pulled the old one off yet. I'll post comparison pics soon. But the new one doesn't seem to show any different gaskets or seals.

Something tells me I got one of the original designs.

OUZO Power

The codes on them are different. And the wire colouring is different. That's the only thing I can tell between the to assemblies.

khelms_98

If you have the part number, the most updated passenger side tail light should have part number 1649064500, whereas the previous and problematic tail light for the passenger side had part number 1648203064. The dealer should have provided the most updated version with better seals, etc.

OUZO Power

Thanks for the info. It's on the car now. I still have the receipt so lets hope the part number is on there.

OUZO Power

Ok I have the most up to date part according to the receipt. Thanks for the info.

khelms_98

That's awesome! Glad that your issue was corrected! Now I need to do the same thing with my driver's side tail light.

OUZO Power

Let us know what that part number is when you do it.

Thanks again.

DAZMAC

So wondered if anyone had overcome this issue as my passenger side (UK) rear light unit has just decided to do the same. I can see 2 Amber LEDs on the indicator have failed so now I'm in the same situation, fork out for MB Dealer parts or repair myself. LEDs are generally inexpensive but its just getting the right voltage and brightness and colour temperature I guess??

OUZO Power

If the LED is burnt that taillight is done. It will work but you cant replace the LED.


Now I had an issue this week on my other taillight. Old part number. The turn signal was flickering when the lights were on.


I pulled it out. Turned it upside down and a cup of water came out.


I then put it in the oven for 20 minutes at 175f and then blow dried it for another 20 mins.


Then I put clear silicone around the outer edge to create a better seal.


Good as new and works as intended. Saved myself $600.

fireken57

...great job ouzo, both of my '10 tail lights threw codes. i removed them but they both were clean and dry and beautiful. so i replaced them with complete units.... spendy but fixed.

OUZO Power

I have my old one in the basement still that I replaced 1.5 years ago on the passenger side.


I betcha if I plug it in it will work fine.


If that's the case I'll seal that one to and give it to my boss who has an ML with a burnt LED.


And I'll expect a raise.

ml3504matic____

lol. Same problem here. Fought with MB canada. At the point where they stoped responding. Found one for $150 lol. Perfect condition. Hehe

Leroy2007

I have an issue that sounds similar, but the lights on my '07 ML350 are not LEDs. The whole assembly will not work...I get separate messages for tail light, turn lamp, brake lamp. But after driving for an hour or so, they start working again. Next day, they have stopped working. Any ideas?

Maj. Dundee

The problem is with the grounding of the tail lamps and M/B devised a small repair harness to solve the problem, and it works.

Part #164 826 00 07 x two.

Leroy2007

Thanks. I will check into that.

Leroy2007

My problem is more than just the tail light...since I posted the original question, I have looked further into it and found that when it goes out, the third brake light and both tag lights also go out...along with the tail light/blinker. They all go out together and come back together, intermittently. Does the harness fix that as well?

Maj. Dundee

When the lamps stop working, do you get a message on the Inst. Cluster that the aux. lights are servicing the stop lamps?

Maj. Dundee

Have you had a leak issue of rain water entering the cargo compartment?

Leroy2007

No evidence of water leak. I get a message for left rear turn signal lamp, third brake light, left tag light, and right tag light.No message about Aux. lights While driving for a while a few days ago, they would all work for a while, then go out for a while, then work again.

Maj. Dundee

You might have had water entry and not known about it, so you have no choice but to check the Rear SAM unit which controls all of the lights you mentioned.

Remove spare tire and everything else including the mat. If you don't have any obvious water, close the tailgate and use a high pressure water hose around the right rear tail light and you might find that water is entering the interior.