I can't find a good diagram or description of which color wires are for the backup lights on this model Mercedes. I have a 2006 ml350, and am trying to upgrade to led lighting starting with the backup lights which need a load resistor, which I have.
Attaching pictures of the harnesses here. Drivers and passenger sides as they have different color wires per side. Thank you in advance

Drivers side

Passenger side

 

So far the best I can tell is that maybe the 3rd wire down on each plug as shown above (what appears to be cream white in drivers side pic, and white w/ black stripe on passenger side) are the backup leads? Can anyone help to confirm? If so, it appears I'd wire one end of the Load resister to this wire, and the other end to the ground, easily found bolted to the body on each side.
I don't have a mechanic manual and difficult to get someone to help me out with backup lights. This has been surprisingly difficult to find, so hoping that someone can help confirm. Or perhaps even if you have any information as to this not being a good idea to begin with? :p

 

I put LED backup lights in my R500 and did not need load resistors. Electrically W251 is mostly identical to W164, so I don't think you will need load resistors. Try it without first.

 

Was actually the first thing I tried. These bulbs even stated that should be canbus error free on most vehicles..but mine ended up constant flashing with an error on dash. So they sent me free load resistor a but I need to be sure I wore them correctly. I was hoping to be good to go like you were.

 

Not all canbus bulbs will work with the W164. I replaced my backup lights with LED. I took the advise for a proper working plug and play bulb from a thread here. I can't recall if it was from the R, GL or ML forums, but the OP had documented which bulbs worked for them. If you search, you will find the thread, I'm sure. I'd spend the money on bulbs rather than play with solder.

 

I got LED bulbs that weren't CANBUS specific. The CANBUS module might actually be screwing with the system.

 

Thank you guys! So, I finally got someone to help me out by shifting to reverse as I needed and found which wires are for reverse. There probably are bulbs I could have used without the Resistors then, but I didn't have much luck when I swapped the front driving lights (tiny lights toward center of vehicle, front) for LEDs. I had to get canbus free ones for them or they'd flash just as these rear ones were doing. But they worked fine with the canbus LEDs.
So, what got me I realized was when I got these leds in the back, they lit up a tiny bit even when not in reverse. I hadn't noticed this before as I was working on them in the daylight. When checking them with a voltmeter, the wires maintain about 9v even when you're not in reverse. Probably for canbus to detect if there's an issue and indicate an error without having to shift to reverse for the computer to detect.
I was correct, in that as pictured above, that the backup wires are the 3rd wire down as seen above. If starting on the harness from the opposite side of ground (to be consistent both passenger and driver side wire-wise) it's the 3rd port/wire up. Mine were almost impossible to tell from the wire next to it colorwise. Driver side it's plain "white", passenger side it looked just like the one next to it, white / black stripe".
Anyhow connected the Load resister to this wire and to ground and they now work perfectly.
SO much brighter! I just need to get some self tapping screws to get those mounted to the metal plate. They're tucked and away from plastic now but I don't like them not MOUNTED, with as hot as they're supposed to get.

Thank you all that had input for the information! This may help me with the other LEDs back there. I may try some Non Canbus-Free LEDs for the other lights just to see if they work without the load resistor.

 

I will definitely search for this as I'm going to be replacing the others soon. Id MUCH prefer this than a whole crapload of load resistors and stripped wires back there. If you happen to be able to find it, since you'd seen it before, could you possibly link here for me as well? If i find it I will do the same for others in the future. Thank you both again!

 

The ones I ordered were Oxilam 1156 canbus. A link below from Amazon, but I ordered them from aliexpress. Better price for me in Canada.


You should be able to find the thread pretty quickly if you searched for Oxilam, I would think.

I am not sure if you're leaving any wiring exposed when you are tapping wires. I would not. Solder and heat shrink are your friends.

 

Crazily enough, that's the exact ones I did order myself. Now it's very perplexing to me..... There HAS to be some difference there...what year is your vehicle?

 

2010 GL 550

Do you have the HIDs or halogens in the front? I have the HIDs, option 615 BI-XENON HEADLIGHT W.ACTVIE CURVELIGHT RIGHT-DRIVE. Wondering if the lighting package makes a difference.

 

You know what? I'll almost BET that does make a difference. That makes perfect sense...yeah mine is the standard halogens. Thats it I'm sure.

 

I am looking at email from aliexpress which I received when I ordered them. They should be the same. I ordered the white ones from aliexpress

https://www.aliexpress.com/item/4001...27527963%22%7D

 

If the package is the difference for the bulbs to not work for you without resistors, add the lighting to the list of overengineered systems on the 164 platform.

 

I'm using these:
I do have the lighting package though.

 

I'm thinking the same thing. That's all I can figure out, and can totally see that making the difference. Until someone comes forward without the light package and having the same lights as mine does (Halogen) I'm going to assume that this is the difference. I'd figured that having power run through the fixture at all times does make sense for the purpose of the info center letting us know if there's a bulb issue before actually needing to use the bulbs...however it's odd that it would be different in that case than for one having HID bulbs. But, those draw power differently as well and dont' they have their own power converters up front? *shrug* a pain, especially if I upgrade all of the rear bulbs...but at least now I know.

 

Do you have LED tail/brake lights from factory? I'm not 100% certain, but I thought that the tail/brake light bulbs were led regardless of the lighting package. I could easily be wrong here. If you do have LEDs, measure voltage to those and compare to voltage with the reistor you installed. See if they're similar values.

I wonder if using the OE tail light bulbs (if LED and, of course, if they are the same type as the backup bulbs) would be an option. Although I imagine someone has probably thought about that before me and determined that it was not a viable option.

 

None of my bulbs on the back side are LED. In fact, I believe the only LED bulbs in this model are the rear view mirror integrated turn signal bulbs?

 

You are correct. Prior to the facelift, all rear bulbs were regular halogen.