ODIOUS

This weekend I got around to installing some HIDs and LED running lights in the R-class (2011) and they look awesome. I wanted to complete the package by switching out the hologen Fog and DRL as well. Since the fog lights are rarely ever on I was going to cheap it out and go with overthecounter Halogens that calmed to have the same look as HIDs. HA! What a joke. I couldnt tell the difference from the original halogens one little bit. So the Fog Lights will go LED for sure.

But the DRL I really wanted to go HID.
I played around with half the day today.
I modified the H7 bulb to fit in the DLR housing and it was a pretty good fit.
But when I hooked everything up (ballast + canbus adapter) I only got 2 short flickers and no light.

There was no bulb out error .. just no light.

I measured the output current for the DRL and I got around 10.8V which is within specs for the ballasts to operate.

I have searched around and have not found anything that would explain the issues with this retrofit. The only thing I can think of is the low voltage (10.8 vs ~12v) but again the specs on the ballasts says this should not be a problem.

When the DRL are on all other front lightning on the R-class are off (and vice versa).


I have been advised that a pair of LEDs connected to a canbus adapter is solution but Im still puzzled as to why the HIDs wont work in this application.


Anyone have any ideas?

TIA

AsianR350

I measured the output current for the DRL and I got around 10.8V which is within specs for the ballasts to operate.

You meant the output voltage not current. You should get 12 volts output or more even ballast can operate at 10 volts. I would re check all the wiring that you have hooked up.
Did you turn the light switch to manual or auto?

ODIOUS

Sorry I may not have been clear.

The voltage output for the DRL measures 10.8 VOLTS. According to the specs of the ballasts they should be able to operate down to 9 volts but I am not finding this to be the case. When I connect everything together I did a quick test of the connections. Immediately after the Canbus module the voltage read 14V. I believe this is because of the builtin capacitor.
But when everything is connected I get 2 short flashes of light from the bulb and nothing else.

I switched everything out with another (known working) bulb, ballast and canbus modules from the lowbeam and it didnt fire up either.

Given the bulb, ballast and canbus modules were swapped and it did not work, the only variable left was the difference in voltage output supplied at the plugs.

AsianR350

Did you swap the halogen bulbs and do they work?
I have HID xenon on low beam lights and fog lights for over five years and have no problem at all.(Switch has to be set at manual. If I forget to turn off the switch, the next time I turn on the engine then the MID tells me that I have a bad left or right bulb).
The capacitor voltage output is always the same as input voltage regardless what the rating WVDC on he capacitor marked. Btw,the output voltage of ballast to the bulb is AC not DC.

Note: Set your day time running light off not in auto because it operates at low voltage such at 10 volts or so.(It is instrument cluster MID setting)

ODIOUS

Swap the halogen bulbs? I dont follow.

From the picture below which setting do you have it on in order to get the DRL to come on?



I was under the impression that the DRL will cut off when the headlights are on (and vice versa).

Also, i never got a bulb out warning while the HIDs were connected. Even when the bulbs wouldnt come on.

Thanks for your help

AsianR350

I meant put back the OEM halogen bulbs.
I set my switch at "6"

ODIOUS

Gotcha...the original halogens are back in the DRL assembly now.


Does your foglight function as a DRL during the day?
I have quad lights down at the bottom of the fender.
2 fogs and 2 DRLs. The DRL only comes on during the day and cant be activated/deactivated by any other means but the menu on the dash console.

I think this maybe the difference here.
If I set the low-beans to ON the DRL will turn off automatically.
I will double check this to be sure.

AsianR350

To able for me to use the fog lights as DRL, I have to turn the switch to position 3 and pull out 1 notch. Since I have LED day time lights, they turn on by itself when the engine is on and off when the engine is off.

ODIOUS

Right, I think i remember your Philips aftermarket LED kit install thread. I think the issue with these DRLs is they dont get 12V like the lows, highs or fog lamps. It gets ~10.8v and the small running lights get ~5v.

AZN Optics has suggested going with an LED bulb which is customized to run at lower voltages as I dont know of any HID ballast that is designed to run at 9v-10v even though their specs claim it will.

AsianR350

Yes, I agree with you. The voltage for the DRL lights is around 10 volts.
My parking lights are running on LED bulbs with the load resistors (to increase the current drawn to fool the computer). LED bulbs draw very low current but voltage is still required 12 Volts to operate as the halogen bulbs.

Note: Bulbs for the running & parking are 5 watts while LED bulbs are less than 3 watts and drawn very little current (that is why we need the load resistor to increase the watts or current drawn)