hoya08

Hi everyone.

The wife’s 2010 ML350 has a Left Mirror Turn Signal error. After not finding a satisfactory DIY on the web to access the mirror turn signal, I created the following DIY from a combination of WIS, youtube, and other MB forums.

However, although I was able to access the mirror turn signal, it appears MB has changed the electrical connector (the Part Number is correct). Short of tapping the wires to make the new turn signal work, does anyone here another workaround? The new turn signal has a 2-pin female connector while the male connector is 4-pin (2 for the turn signal, and 2 for the puddle light).

DIY:

Step 1: Turn the mirror inwards as far as possible.

Step 2: Grab the exterior of the mirror and pull with your hands. Gently pull and tug until mirror pops off. Be careful once the mirror comes out. There are 3-wires attached to the mirror.

Step 3: Push the inner top tab to release the front mirror cover from the automatic closing mechanism. Gently push down on the top of the front cover and release the other two top tabs.

Step 4: Push the inner bottom tab to release. Release the other bottom tab and side tabs. The front cover is now free. Feed the mirror through the front cover.

Step 5: Use a very small flat head screwdriver to depress the “white” electrical retaining clip.

Step 6: Push the top tab to release the back mirror cover from the automatic closing mechanism. I can’t recall if there’s one on the bottom too.

hoya08

Step 7: Pull the back mirror cover outwards from the vehicle.

Step 8: Unclip the electrical connector.

Step 9: Disconnect the male (black) and female (white) connector.

hoya08

Next Steps are only if you plan to remove the Turn Signal

Step 10: Unhook the positive/negative wire.

Step 11: Use T10 to unscrew the turn signal.

Step 12: Unclip the turn signal from the cover

You can see in the attached photos, the new female end is different from the original end. I can't seem to disconnect the positive/negative wires from the 2-pin female from the new signal, nor the two wires from the original signal. The original wires are connected to a 4-pin female end.

So, short of tapping the wires, is there another workaround?

OUZO Power

So the flood light and the LED turn signal come together on the same harness?

hoya08

Yes, they're on the same harness.

I could not remove the wires (the turn signal nor the puddle light) from the harness. I couldn't remove the wires from the new turn signal harness either. Hopefully some of the experts here can chime in with a method to disconnect the wires.

PelicanParts.com

Nice detailed DIY. Great use of images too. Good job.

-Luccia

OUZO Power

Is there a chance you got the wrong model for another line?

hoya08

The incorrect part number? The new part is the same part number as the "original" item, A 204 820 07 21

hoya08

Update:

It turns out the part I ordered was indeed incorrect. I ordered based upon the turn signal part number! The correct PN which includes the correct harness for the puddle light is 1649061300.

OUZO Power

So what model was that for?

hoya08

204 820 07 21 is for the C-Class.

What caused confusion is that the Part Number above is clearly stamped on the original ML turn signal. The correct PN identified in post #9 is not found anywhere on the original ML turn signal!

The correct part requires removal of the turn signal and the entire 4-pin female harness, to include the wires connecting to the puddle light.

It appears MB uses the same turn signal on multiple models, but with at least 2-different wiring setups, with or without puddle lights.

OUZO Power

I need to replace mine also. LED works but cracked and puddle light not working and it's not the bulb. But I can only see going to the dealer as the safe bet. I did a search on ebay and even thought they come up nobody shows a pic of the double harness.

hoya08

Unfortunately this is the only photo I found online which shows the correct harness, so it's not as large as my other photos.

If your puddle light bulb is not the problem, and your turn signal works, it appears the puddle light wires from the 4-pin female may be bad, or a possible ground at the socket.

This DIY is quite simple if you decide to tackle it. With the instructions above, it took me less than 10 minutes to remove the mirror, housing, and turn signal.

OUZO Power

Found one with that exact pic. I'm going to give it a try.

STLML350

Dear ML350 owners, I thought I had the same problem with a bad LED but my wires cracked and broke from using the mirror fold in option. I was able to pull the tape on the wire harness back far enough to strip, solder and shrinkwrap and then retape the complete wire lenght . Took a couple hours but bet I saved at least a $300 bill.

OUZO Power

SOB look what they sent me. I ordered what I thought was the right one off ebay and listed with the pics above & the double connector and they sent me a single one.

Crap.

IMG_3994.JPG

marcel56k

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dnh1959

Hoya08, I have a similar problem. My passenger side mirror was the first to go. Bought the LED from the dealer, which was the right one, for $100.00. (Way to expensive) swapped it out but it didn't fix the problem. Took it to the dealer thinking the LED they sold me was bad. They confirmed I installed it properly but that I had an "open" in the wiring harness and they wanted $800.00 to swap out the entire mirror, casing and all. I thought this was ridiculous since it was just one wire in the harness that was "open" so I tried to determine which wire was open but was unsuccessful so I found the inside unit with wiring harness used for $150.00 and swapped it myself which fixed the problem. Three months later the same issue on the driver's side so I found another unit for the driver's side for $120.00. Swapped it out but it did not fix the problem??? I know it could be the LED so I found one online for $40.00 Waiting for it to arrive. I had to of course pull of the inside door trim to be able to unplug the two wiring harnesses from the door in order to install the new motor. This is a poor design with respect to the wiring harness in that it obviously deteriorates over time with the mirror folding in. In the mean time, while I wait for the LED to arrive I sure wish I could find a wiring diagram so I could eliminate that as the problem. Any help would be greatly appreciated! Thanks!!!

STLML350

In my case fixing the wires was not all that hard. The mirror heating wires were still good , the led wires were broken but I twisted one of the wires and then held the other wire together and turned on the blinker and it worked. Im sure I would not have hurt the led if I turned the blinker on it didnt work.