HID DRL fix/workaround

[PurpleGoat88]

This requires the use of a relay harness (which I recommend anyway) and a 4700uF capacitor

 

Ok,

When DRL's are active, you car is supplying the following signal to your driving lights:

 

_ _ _ _ _ _ _ _ +12v

_________________ Ground

 

That's Correct, it 'Pulses' the current to lower the intensity of the light. This works perfectly for Filament bulbs, as you are simply heating a filament which produces the light. But when sent to the relay, it will cause the relay to latch and unlatch repeatedly which will cause flicker.

 

HID's however, need a constant current flow to them, such as the following:

_________________ +12v

_________________ Ground

 

 

Now, most people are over complicating things, by making the Fog's DRLs and such, but I don't want to fiddle around with the lights everytime I get in the car, so this is what needs to be done to be able to keep the Auto function of the headlights.

 

 

We will, by the use of capacitors, turn the DRL's Pulsing current -_-_-_ into a smooth, constant flow --------

 

So, we aren't relocating the DRL's, we are simply going to use HID's as DRL's AND Driving lights. Perfect! This is exactly how most Audi's and BMW's function anyways.

 

So, here is the miracle solution:

 

Using a 4700uF (That's microfarad) capacitor (A pair should run you 4-5 bucks at most) we are smoothing out the Pulses and sending a constant supply to the Relay.

 

This is called a smoothing or reservoir capacitor. What it does, is on a Positive pulse, it charges, and in between pulses it slowly discharges. The bigger the capacitor, the slower the discharge:

 

Without Capacitor:

 

 

With Capacitor:

 

 

We can see after the capacitor, we have an almost linear voltage. How do we make this as linear as possible?

By using a capacitor as big as the 4700uF. This keeps the relay latched so that it doesn't interrupt the current flow to the ballast.I do NOT recommended using this without a relay, you shouldn't put this in parallel with the ballast itself.

 

And for when the driving lights go on, the constant +12v will simply keep the capacitor charged and this won't affect system performance as it basically will stay there fully charged until it can discharge. And when you cut power to the light, the capacitor will discharge quickly enough as to not allow the relay to flicker. The ballast see's it as the current beeing shutoff and not a pulsing current.

 

 

So, all you need to do, it simply splice a capacitor between the +12V and GROUND wire leading to the Latching relay, such as my diagram below shows:

 

 

Enjoy!

 

Credit to mtlsportgt on mazda3forums.com

[2014 Sporty Shorty]

Great write up, I like when people make question proof threads. Now that you have figured this out for us I will actually order my morimoto lights now without the drl worry. Thanks for the help.

[clayp]

So is someone already producing this as a kit?

[PurpleGoat88]

Not that I know of

[clayp]

Not that I know of

http://www.theretrofitsource.com/product_info.php?products_id=238

 

this morimoto adapter uses 6800uF capacitors. Do you think that would work?

[PurpleGoat88]

Not that I know of

http://www.theretrofitsource.com/product_info.php?products_id=238

 

this morimoto adapter uses 6800uF capacitors. Do you think that would work?

 

Unlikely as that doesn't hold a relay on. The relay is key. And it clearly states does not work on DRL's

[PurpleGoat88]

 

final product. 5000k hid low beams.

[clayp]

so did you do the relay and capacitor as shown? Someone on HIDplanet forums also recommended wiring in a diode so that the capacitor could not discharge backwards

[PurpleGoat88]

so did you do the relay and capacitor as shown? Someone on HIDplanet forums also recommended wiring in a diode so that the capacitor could not discharge backwards

Yes that's how I did it and I don't think a diode is necessary as a capacitor only discharges one way. That's why it has pos and negative poles.

[Tungsten-09]

I did this yesterday and i have no more flickering!!! thanks..D. got a pack of 6 4700uf capacitors on amazon for 10 bucks shipped incase people need more..

[jcheller]

Is this the type of relay I need?

 

http://www.radioshack.com/12vdc-40a-spst-automotive-relay/2750001.html#.VO9bsXbnYdV

 

I'm assuming the DRL's on a 2009 Silverado LT are using the same "pulsing" flow?

[Jaycreek7908]

I'm surprised TRS or DDM doesn't have a kit specifically for this

[Dbeto54]

I'm surprised TRS or DDM doesn't have a kit specifically for this

They do, its called HID Error Canceller

[Colossus]

You lost me with all those diagrams. But great article none the less. Thanks

[Jaycreek7908]

So all I need is whatever kit I want with relay, with capacitor link as in the picture and I'm good to go? I've had hid kits in every vehicle I've owned but never had to deal with canbus modules.

 

For that matter, what's the difference between canbus modules, capacitor links, and error code eliminators