Actually I'll just post some info that we found a couple months ago now.

Basically, from what we discovered is that the ETACS ECU sends a PWM signal to a field-effect transistor or MOSFET of some sort to toggle the lights on/off quickly. It appears that the ECU internally grounds a pin that is input to the MOSFET which turns it "on" to complete the circuit to the low-beams to turn the low-beams on. You can confirm this yourself by turning the lights off and the key off and grounding pin "2" of the MOSFET connector (with it plugged in) to the car's chasis (we ground it through a resistor just in case).

The PWM signal from the ECU is a 35% positive duty cycle at 55Hz. It is inverted at the MOSFET to a 65% positive duty cycle.

My suspicions are that a very simple way to disable the DRLs is to use a resistor/capacitor circuit to filter the ECU's PWM signal (leaving the wire at 12v), except when the low-beams are turned on at which point the ECU leaves the pin grounded. I had drawn up a sketch of this, but can't find it now and I never tested it (I wanted to buy a spare MOSFET from the dealer before I proceeded with experimentation). I've also been fairly busy on other projects, so if you have time to look into it, you'd be benefiting everybody!

Here is the scope cap of the PWM signal. I think this was at the output side of the MOSFET (to the headlights):


Here is a "BEST GUESS" of what the circuit looks like in the car. Pin 4 is the power that is switched to the headlights Pin 1 & 2 are guesses as to how the line is held high and how the ECU controlls it -- note that it contradicts what the service manual shows. Pin 3 is split and goes to both low-beams and is grounded at the headlight somewhere. Again disclaimer: This drawing is 99% likely to have errors, use at your own risk!


Here is the "official" schematic from the 08 Lancer's factory service manual. Looking at this, we could mount our circuit right in the passenger compartment since there really isn't much room in the engine relay box:


Good luck!!

 

cool,

I just got a job offer about a week ago so i'm trying to find an appartment and move and get all setup before I start work. But this gives me something fun to think about. Where'd you get access to the oscillioscope? Or, any clue how much it would cost to buy one. I know the ones we used at school cost like 10grand a piece so i always assumed that i wouldn't be able to afford one.

 

The scope we used was a friend of mine's. That said, a cheap digital scope off eBay for $200-$300 isn't too hard to find and surely would be good enough for most home projects. Heck, even a USB-based scope and a laptop would probably be a worthwhile investment. Or you could ask to borrow a scope from your place of employment.

Just be careful when experimenting -- especially in this case where you could (at best) lose all your low-beam headlights if you fry the ETACS ECU's port pin or the MOSFET.

 

Here is a more complete picture from the service manual. It suggests that pins 1 & 2 are mixed up in my own drawing above, which given that I drew it before I ever got my hands on the service manual drawings is pretty good I still think they're somehow connected together internally though we have to do some more testing to know for sure.

 

Ok, so I did some testing based on brian360's info and we should be able to eliminate the DRL's. Basically, all pins are connected as normal, except for pin 2 (the mosfet control pin). This pin is connected to the socket through a 33k resistor. Then a 2.2uF electrolytic capacitor is connected from pin 2 (on the mosfet side) to ground. The mosfet has an abnormally high turn on/off threshold (around 10.5V), thus the need for the 33k resistor. With this circuit, when the DRL switch is on, the pin 2 voltage is 11V which turns the MOSFET on and the headlights off. When the headlight switch is fully on, the pin 2 voltage is 10V which turns the MOSFET off and the headlights on.

Happy Driving!

 

Sorry putting my day time running light on makes me feel a safer driver
try not using your headlight at night in the city and just use your Day time running light

You feel like saving a lot of energy on the headlights and the bulb might last longer.
I only use my regularheadlights onwhen it'sreally really dark.

 

So afeudale are you saying that if we just added a greater resistance than the 33k it should disable the DRL?

To everyone who keeps saying that DRL are so much safer and we shouldn't be trying to disable them: Why do you think it is safe to drive down the city at night with just DRL? That means you have no tail lights and are extremely less visible from behind. Also there are several reasons that I can think of that people need/should be able to control their headlights.

1. Entering a secure check point at night such as military bases. DRL really pisses the guards off and if it would be helpful to turn them off.
2. Leaving home (apartment) in the morning and don't want to throw headlights in peoples faces that are trying to sleep because you parked in front of their window.
3. The girls at sonic don't really like walking out of the door to deliver your food with lights shining in their faces.

I know these are all trival points but my point is i'm not trying to be less safe or save the world's energy by turning my DRL off. I just want the OPTION to do it.

 

That's Not a Good Excuse.

DRL is important

running light in the city you can still click on the Taillight without using your Regular Headlights. Put in the MIDDLE on your 2008 Lancer headlight ****.

If someone is Senile Like older People and drive at night and forgot to turn on his/her headlight the DRL does the work for themor if you were drunk and forgot to put your headlight but DRL saved you being pulled over by the State.

Military Base My Uncle lives in Jacksonville Florida and he drives a car with DRL.

he never get yelled by the guards and OF COURSE AT NIGHT YOU NEED A HEADLIGHT probably the guard was mad because you were driving without a Light.

I saw 15 cars last night on Foggy Massachusetts WITHOUT HEADLIGHTS ON only corner lights were on. Is that a very good example. Everyone were honking and clicking their lights to warn those drivers without HEADLIGHTS.

Actually DRL lights does not not heavy Beam it ISmore pleasing to the eye than regular beams. TRY IT?

I don't like Sonic Food by the way I like White Castle

Yap We complain alot about DRL

Why did Engineers from Germany and Japan Ever develop the DRL if it is not safe.

Try doing 80 mphon the highway on sunny day without DRL.
The car in front of you will not see you coming from behind or fromthe side. Because you were doing 80 and you think people can easily see you. Especially 100 mph with turbo on

Did you notice that all Professional street racers has multiple lights one when they speed?
Because one thing a State police hate is speeding without lights on and a Tail Gater.

 

For those of you who want to shut the DRLs off on their 2008lancer (like me) I contacted a local dealer yesterday. One of them toldme it is impossible to do, the other one I called said it is very easy to do, all you have to do is bring the car in to the dealer, it takes about a 1/2 hour for them to hook it up to the computer and they shut them off!! Costs about 45 bucks which I think is well owrht gettign rid of those stupid things. Now I can put my HID's in

 

Hi. Can you upload some pictures of the instalation? I have Outie and I will install OEM HID headlights and I need to do this modification. Thank´s in advance