mkhurley

I have a 2007 E550 4-Matic.......Will setting up the headlights/foglights on relays so they come on whenever the vehicle is on set off any codes in the system??

I've done this on previous (non-MB) vehicles and prefer to run with these lights on all the time. I wouldn't take the factory wiring out of the loop, just put in relays (and fuses of course) that would activate these circuits whenever the ignition is on.

Sathinas

Why would it throw any codes if done properly?

But why go through all that hassle? Just set your lights to "auto" and cover the light sensor on the dash (or where ever it may be located), with some black tape.

Alternately, just turn the lights on at the switch.

mkhurley

I've read thru the forums a bit and find that the MB will throw codes if a light is out, or if say LED's are installed, the system recognizes this and a code is thrown for it. I'm just wondering if this is the case with what I'm considering.

The problem with Auto, my wife has had it happen once already and it says this in the owners manual also, they will shut off due to oncoming headlights. She said the truck had on high beams and once he'd passed the headlights came back on again, but them going out like that is not something I'm looking for. It appears the sensor is behind the windshield above the rearview mirror with what is probably the rain sensor also and tape isn't an option, it's a MB, not a Pontiac (my son did the tape in his Grand Prix).

Yeah, you can just turn on the switch, and it says you should in the owners manual, but who pays this much for a car and has to turn the lights on/off everytime they get in/out. I've run my Yukon Denali (that has auto headlights also) like this for 6yrs now, I don't think about headlights anymore. Keeping the factory wiring in place allows things like the exit feature to work when the vehicle is off and lights turned on/off with different operations of the key fob.

lkchris

There is NO reason to do what you suggest, as you can "program" DRLs via the multifunction display (speedo display).

If you don't have an owners manual, your dealer can get you one or you can order one at 800.for.merc

You won't get always-on foglights, which is dumb in any event. Foglights are for fog.

Sathinas

Duh!

Didn't even think of that one. Chris is absolutely right.

mkhurley

I already have the DRL's on, thank you. I'm not trying to justify or explain reason, this is something I want to do, that is really all that matters. I am not suggesting it either, what others do with their lighting is not of my concern. I simply want to know if this will throw a code or not.

You can also download the owners manual in PDF format for free from www.mbusa.com after signing up as an owner. Although, I have the one that came with my vehicle, but again, thank you.


I've never owned a vehicle that forced me to say "I have way too much light out front." And, I will get always on foglights if I wire in a relay that does just that, I know this, I've done it before.

Then what is the purpose of MB using them when one is turning left or right. (Notice this is a statement, not a question)

Sathinas

Alright. You have fun with that.

Do what you want with your lights. Maybe even throw some more on there, since you can't seem to take other's suggestions with a grain of salt. No... no need to justify anything. Good day.

PS. Let us know when you get them LED's installed, and if you're nice, I may tell you what size of a capacitor you'll need in order to "fool" the lighting computer.

mkhurley

Thanks, I will.

I had already done his suggestion, that setting does not produce the result I want.

If I were installing HID's I would pick up a couple 2200µF capacitors rated at 35 volts, but for LED's, I'd rather use resistors to take care of the job, if I were installing any, which I'm not. So while I appreciate the offer to help with that, it won't be needed, but again, thanks.