Disable DRL's

[team dougherty]

Hello, I have looked all over the internet for a way to disable the DRLs, Daytime Running Lights, on my car. There are solutions out there but they also disable another feature that I like. The car does have a way to disable them but it must be done every time the car is started. a real pain. I know what I would like to do to disable them automatically but I am not an electronics expert by any degree.

In my search for a solution, I was looking how to use a 555 timer, way over my head, I found this site. I looked around and found some great posts and a lot of smart people. Hopefully someone here can design and build the circuit for me.

Here is what I would like.

The DRLs can be disabled by pushing the dome over ride button four times within 6 seconds after the car is started. This has to be done every time the car is started.

After some investigation I found out the the dome over ride switch is a double action switch. Push for on and push for off. all the switch does in take an output from the BCM, Body Control Module, and sends it to ground.

The output from the BCM is 12 volts and when grounded 12.25 ma of current flows. The picture below shows two needles in the plug. one is the wire that goes to ground the other from the BCM. they both go to the dome over ride switch when plugged back into the switch housing.
**broken link removed**

when those two pins are connected and disconnected twice I get the familiar beep beep from the car that the DRLs have been disabled.

So, I will need a circuit that will sense when the car is started, there a several wires that I can tap into that are only hot when the car is running, and wait a half second, close a set of contacts for a half second, the open for a half second, then close for a half second then open and wait til the next time the car starts and then repeat the whole process.

This will give me exactly what I want. Can any one help me with this?

Thanks for taking the time to read.

Paul

 

[ccurtis]

So, I will need a circuit that will sense when the car is started, there a several wires that I can tap into that are only hot when the car is running, and wait a half second, close a set of contacts for a half second, the open for a half second, then close for a half second then open and wait til the next time the car starts and then repeat the whole process.

If the maximum toggle count does not have to be exact (i.e., the dome signal can be toggled a few times beyond your requirement) the circuit could be simpler. Also, a solid state switch would be better than a set of contacts.

At least you can disable DRL without cutting wires. That's an improvement over some cars.

 

[team dougherty]

If the maximum toggle count does not have to be exact (i.e., the dome signal can be toggled a few times beyond your requirement) the circuit could be simpler. Also, a solid state switch would be better than a set of contacts.

At least you can disable DRL without cutting wires. That's an improvement over some cars.

The toggle count has to be exact. If you toggle it 4 times it will turn the DRLs off then back on.

 

[cachehiker]

No mention of the make and model but on my Subaru it was as easy as removing a power resistor that was in series with the lights in day mode and shorted in night mode.

 

[crutschow]

So what's your beef with running lights? Seems like they would be a safety factor.

 

[team dougherty]

No mention of the make and model but on my Subaru it was as easy as removing a power resistor that was in series with the lights in day mode and shorted in night mode.

On some cars that works. On my Saturn I just had to keep a set of contacts on a relay from closing. On my 2002 GMC Envoy the DRLs are all controlled by the computer. It uses PWM at around 70% duty cycle to run the DRL's

So what's your beef with running lights? Seems like they would be a safety factor.

I did not want to turn this into a debate over DRLs. Since you asked. They burn out bulbs faster, they can cost 1/2 MPG reduction of fuel mileage and there has not been much proof of any increased safety.

https://auto.howstuffworks.com/fuel-efficiency/fuel-economy/drl-gas-consumption1.htm

 

[WTP Pepper]

You want to modify the electrics of your car!!! In the EU you could be sued if you change such safety critical systems as vehicle lights and were involved in an accident.

Insurance companys here are very explicit in asking you about modifications from re-chipping the engine management unit to changing the bulb in the headlight.

If it's not approved by the maker of the car (and they are intensive checks in terms of safety) then you are out on a limb. Some smart lawyer could say it affected the brakes etc and you are liable. Despite what we may thing about common sense, could you afford to prove otherwise in a Court of Law?

In the 80's I fiddled with all sorts of wiring in my old Ford but sadly things have changed here.

 

[strantor]

in America nobody checks under your dash to see if you've modified any electronics. Especially the insurance company, they never even set eyes on the vehicles they ensure. The only one who comes close is the annual state inspection which is carried out by a service station attendant.

 

[gerty]

You don't say what vehicle...
On my Silverado all you have to do is apply the emergency brake, moving my pedal down just 1 click will disable the
DRL. Easy to try, no wiring modifications.

 

[team dougherty]

You don't say what vehicle...
On my Silverado all you have to do is apply the emergency brake, moving my pedal down just 1 click will disable the
DRL. Easy to try, no wiring modifications.

Then you have to look at the brake light in the dash and both of my cars will beep as soon as the car moves with the e brake on. As stated in the first post the car already has a switch to do the job. I want to do it automatically.


Please can we stay on the original topic? I just want help designing and building the circuit.

 

[ccurtis]

I can design it, but I can't offer to build it.

 

[team dougherty]

I can design it, but I can't offer to build it.

That is Great. Thank you very much. Does the VSS go to the 12V switched source so the circuit knows when to fire?

 

[ccurtis]

You're very welcome. Yes. The circuit resets and starts a new cycle each time +12V power is applied.