I have to replace the red socket for my xenon light because it is damaged but both wires are the same colour. I bought a replacement socket and the wires on it are red and black. How can I know which wire is positive or negative on the oem setup?

 

Hmm hard to tell.

What I suggest is you cut ONE wire on the factory socket, and use a multimeter (on resistance or diode check) to find out which wire it is on the socket (inside center or outside ring). From there, find that same wire on your new socket, and you'll know which wire goes to which.

 

Wouldn't I be able to test if I removed the little plastic cap on the socket? It exposes the wiring where its soldered to the socket

 

That would work too, I didn't realize it was two pieces

 

I'm a noob with a multi meter.

 

Stop! Don't do this, this is unsafe. The voltage running through the power wire when the xenon ignites is near 24,000 volts. It is ramped up to ignite the xenon burner. There are little yellow stickers that are warning you of this too. Do not use a multimeter (12V) on a circuit that is rated much much higher.
The only safe way to determine which is positive and negative is to use the star finder and check the wiring diagram.

edit:

There is a TIPS case from Mercedes Benz regarding the replacement of the xenon burner. Here are the steps:

Caution:

Risk of death due to high voltage in xenon headlamps. Do not touch parts which conduct high voltages. Persons who wear electronic implants (e.g. heart pacemakers) must not carry work out on xenon headlamps. AS82.10-Z-0001-01A.

Repair solution:

1. Detach front wheel (Remove/fit wheels, rotate if necessary, AP 40.10-P-4050Z)

2. Remove front fender liner (AR88.10-P-1300P)

3. Detach headlamp connector

4. Unlock housing cover of front lamp unit from the tab and remove

5. Turn ignition module plug counterclockwise and remove (Figure 1)

6. Remove and dispose of retaining collar (Figure 2).

7. Remove burner

Note: Do not touch the glass bulb of the burner with your bare hands. Use a grease-free,

soft cloth.

8. Cut off plug as close as possible to ignition module (Figure 2) and dispose of ignition module plug

9. Cut off three supply lines to ignition module (red/black/green) as close as possible to ignition moduloe (this isolates the ignition module in the headlamp) (Figure 3)

Note: The three strands should be cut individually.

Do not cut them all together with the side cutting pliers to avoid short circuits between the strands.

10.Connect adapter cable to supply lines

with solder connector (A002 546 13 41) (see Figure 4)

Take care not to damage the headlamp housing with the hot air gun!

11.Wrap solder connector with fabric tape

12.Remove four locking holes in lamp retaining collar A230 826 0089 with a screwdriver

(see Figure 5)

13.Insert burner and fix with lamp retaining collar A 230 826 0089

(ground contact at the bottom, see Figure 6).

Note: Do not touch the glass bulb of the burner with your bare hands. Use a grease-free,

soft cloth.

14.Fit new ignition module and lock in place (observe installation position: Figure 7a= right headlamp, Figure 7b= left headlamp)

15.Attach housing cover of front lamp unit

16.Perform function test of lamp units

 

I'm not stupid I know its 24,000 volts. I had the battery disconnected when I play around there.

My plug is burnt, so I cut the plug off and soldered on a new "aftermarket" d2 plug. I didn't know which was positive or negative so I tried it one way, then switched it the other way. Neither way worked so I am a bit confused.

 

Perhaps the headlight control module is also no good.

 

Is that the silver module screwed in under the headlight?

I think it might be easier to buy a complete headlight assembly from a VGA car.

Another question; I bought 6000k d2 bulbs, most probably chinese for $35 each. Would those bulbs damage my system?

 

I don't think you quite understand how a resistance/loop check works.

 

I assure you I understand automotive circuitry just fine. I read it as you were asking him to probe for power at the burner and I was like

Measuring resistance and measuring voltage are two different things.
and yes TylerF the little silver box under the headlight is the control unit. If yours is bad let me know, I have a perfectly functional one that I am not in need of just sitting in my toolbox that I could sell you for cheaper than you'll find elsewhere

 

Can you add me to Facebook? You seem to know what you're talking about. Search for tylerfisher@gmail.com ; Thanks

 

No, that's why I told him to cut one wire first so he could have both ends - wire and socket.