Welcome to the North American Subaru Impreza Owners Club Friday April 25, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Electrical & Lighting

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 06-10-2009, 01:14 PM   #1
Azxster
Scooby Newbie
 
Member#: 185659
Join Date: Jul 2008
Default How to rewire DRL to fog lights?

I tried searching but couldn't find anything.

Does anyone know how to rewire such that the fog lights acts as the DRL?

Car: 2008 Impreza
* Registered users of the site do not see these ads.
Azxster is offline   Reply With Quote
Old 06-11-2009, 02:05 AM   #2
trueno16v
Scooby Specialist
 
Member#: 175170
Join Date: Mar 2008
Chapter/Region: MWSOC
Location: Milwaukee, WI
Vehicle:
2005 WRX Wagon
owl + bungee cord= my a$$

Default

Ummm, maybe use the foglight mod to make the foglights come on with acc power?
trueno16v is offline   Reply With Quote
Old 06-11-2009, 04:16 AM   #3
aboothby
Scooby Newbie
 
Member#: 111994
Join Date: Apr 2006
Chapter/Region: TXIC
Location: Austin, TX
Vehicle:
2006 STI
WR Blue Pearl

Default

That would take quite a bit of re-wiring but it can be done and with a small ammount of pre-design.

The first problem is that the DRL function and the regular headlights are controlled by the same wire on the same bulb. The DRL is simply the product of a relay switch placing a resistor in series with the bulb to lower the voltage, thus reducing the luminous output.

The best way to go would be to set it up so that when the relay - which normally switches to apply the resistance - will instead divert the voltage to the fog bulbs. If you want to have control over the fog lights when the lights are on, you will need to incorporate diodes into the design.

The only true way to start and have it done right is to examine the electrical schematic in the service manual and re-draw the circuit so that it will do what you want, then re-wire the car accordingly.

It is not a hard thing to do, but it is an important step if you want to do it right and have it be electrically sound.
aboothby is offline   Reply With Quote
Old 06-22-2009, 09:27 PM   #4
Henry H
Scooby Newbie
 
Member#: 184330
Join Date: Jul 2008
Location: Southern California
Vehicle:
2008 Impreza 2.5i
Dark Grey Metallic

Default DRL fog lights

There are a few ways and options in doing this. First, what do you want it to do? Do you want them to behave exactly as the OEM highbeam drl (dims on and off when the car goes form Part to drive and/or when the handbrake is pulled)? Or do you want them to be fully on when your car is on?

1) If you want the OEM-dimmed way, you need to do some wiring behind the front bumper (a bumper cover removal will make it much easier).

2) If you want the simple on off way (only on when key is turned to ON position) then the wiring will be under the dash. That has actually been addressed in another thread:

http://forums.nasioc.com/forums/show....php?t=1706871

I'd opt out for the second method. Its easier and you dont have to go fishing around for the DRL module. Furthermore, the second mod only needs like one short 22gauge wire as opposed to several longer lower gauge wires for lamp illumination.
Henry H is offline   Reply With Quote
Old 06-22-2009, 09:59 PM   #5
Henry H
Scooby Newbie
 
Member#: 184330
Join Date: Jul 2008
Location: Southern California
Vehicle:
2008 Impreza 2.5i
Dark Grey Metallic

Default

Quote:
Originally Posted by aboothby View Post
The best way to go would be to set it up so that when the relay - which normally switches to apply the resistance - will instead divert the voltage to the fog bulbs. If you want to have control over the fog lights when the lights are on, you will need to incorporate diodes into the design.
Good point aboothby, but I am worried about the diodes. I assume that the diodes will positioned after the DRL resistor in the right bumper to prevent the voltage going back towards the DRL module when you supply the full 12V to light the fogs, but that type of amperage will sure burn up most diodes, unless you dont mind paying a lot of money for a high amp diode.

I only assume that's the location you anticipate for the diode to be because I don't forsee how you can break the circuit of the drl relay (or module) when you turn on the fog lamps. Unless there is a relay that will break a circuit when a current is passed through the relay's switch.

I know, I know, if the highbeams are able to do it then why can't the fogs do it? Well I suspect that is what the DRL module is doing (btw, I can't find that damn module anywhere on my 08). You can swap the connection of the wires after the hi-beam\fog switches before the DRL module, that would be one solution (that's like re-allocating the DRL module to sit on the fog light circuitry). Or we can just swap the the wires just before the lamps and after the DRL module. But you don't wanna look stupid when you try to flash someone and wind up turning on your fog lamps. Those options will be a serious PITA and not worth the trouble at all.

But, as I stated in my last post in option 2, the easier way is to just do a simple wiring under the dash and be done with it. Just leave your fog lamp in the on position and the fogs will switch on and off whenever your key is turned in the appropriate position.

Cheers!
Henry
Henry H is offline   Reply With Quote
Old 06-22-2009, 10:53 PM   #6
Henry H
Scooby Newbie
 
Member#: 184330
Join Date: Jul 2008
Location: Southern California
Vehicle:
2008 Impreza 2.5i
Dark Grey Metallic

Default

AZXSTAR!!!

I just realized you already asked this question on the forum I showed you.

There is a much easier solution IF you still plan on having HID fogs!!

First, a couple things to address.

1) Don't allow the fogs to dim. That does not work for HIDs. Ballasts must get a constant 12 volts. The dimming that you see is caused by the DRL resistor. 12 volts come in hit the resistor and a lower voltage goes out to the bulbs. If ballasts gets less than 12 volts for the HIDs you'll get flickering (not good)

2) There are many that advocate against HID fogs...mainly because of the brightness it puts out that can blind others. I myself have HID fogs but I aimed them real low so the beam will only catch the road.

3) The wires that sends 12 volts to turn on the DRLs goes to the resistor, the voltage drops and turns the hi-beams "haflway." We want to BE SURE the wires going TO THE RESISTOR is able to sustain 30 amps. This we dont know for sure. If it can, your mod is easy, if not then we need to add a relay circuitry.


On to the mod (the easy, not-really-preferred way):

***DISCLOSURE: The steps for this kind of modification assumes that the wires coming from the positive terminal of the battery to the Daytime Running Lamp (DRL) Resistor have a proper guage to operate two halogen bulbs without the consequence of overheating and/or electrical fire.***

*Disconnect neg terminal of battery

-Remove the bumper cover
-Locate the DRL Reisistor (a ribbed aluminum casing surrounding a ceramic block with a wire coming out of both ends) approximately the size of a boxed soap bar. It should be near the other horn speaker.
-Unplug and remove resistor
-At each fog lamp identifiy the 12volt wire and cut it near a couple inches from the harness. Cap off the cut wire on the 12 volt feed side. Don't do anything to the ground wire.
-Run a wire (approx 10 guage) from the wire at the removed DRL resistor to each of the wires you just cut at the fog lamp harnesses (harness side only)

Final notes: By removing the resistor we effectively have a full 12 volt source that acts like the OEM DRL (always on when car is on/not in park/parking brake down and turned off otherwise). However we now do not have ANY control over the fog lamps (neither did we with the highbeam DRL).

Personally, if I really wanted my HID fog lamps to act like the OEM DRLs I would add another relay circuitry to prevent a possible electrical fire. The relay addition method would require a bit more work. But since you want an easy way, there you are. I cannot find a fuse for the DRL so I cannot assume whether or not those wires are safe for this kind of application.

Henry
Henry H is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to remove 06 wrx fog light covers. asherbo Interior & Exterior Modification 15 12-16-2009 07:22 PM
How to enable DRL daytime running lights on JDM GC8 WRX? stigc8 Interior & Exterior Modification 12 04-18-2008 09:20 AM
how to swap DRL to small parking light on 07?? cowboysuby Electrical & Lighting 4 01-15-2008 12:25 AM
How to pop out the fog light compartment cover on non-fog light STis (06) magnumeagle Newbies & FAQs 5 03-28-2007 07:39 PM
Can someone please post directions or url on how to mod a MY00's fog lights s-one Interior & Exterior Modification 0 06-23-2001 09:23 PM


All times are GMT -4. The time now is 02:42 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.