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Simple and cheap DRL using the highbeams

Posted: Thu Dec 06, 2007 12:20 pm
by EricN
Sometimes I amaze myself. I was thinking about how I hate the lowbeams coming on with my key all the time especially during cold starts and got to thinking how I could cut down on the draw. I thought of wiring it to the park brake switch (might still do that) but then I started thinking about using a dimmed high beam for the DRL. 2 hours later I have it designed, installed and working and it is so stupidly simple and cheap.
Keep in mind I suck at math so I am not sure it draws any less amperage, but it is still cool.
I will add pics and a step by step in the wiki tonight but for the electrically inclined, here is the text version.

Buy a standard automotive 12v relay that is normally closed and when energized, closes a different circuit (dpdt????) basically any relay you buy from Lordco will have a 90% chance of being the one.
The terminals should be marked 85 and 86 for the relay control circuits and 30, 87, and 87a for the load circuit.

Remove the drivers headlight assy, cut the black ground wire that is for the highbeam bulb only. The side of that black wire that heads to the bulb connects to terminal 30 on the relay. Connect the other side of that wire (the side that goes to ground) to terminal 87a (the one in the center of the relay), connect a switched 12v that can handle the highbeam power to terminals 87 and 86. Now, the wire that is power for the lowbeams (I think mine is light blue or something), dont cut it but splice a wire off of it and connect that to terminal 85.

Under the dash, remove the Highbeam fuse (#6 from the top left when looking at the fuse box, 15amp I think)

Ok, that is as far as I have gotten. I need to get a diode today to finish the last step, which will be to put that diode in line with the fuse. I will probably remove the fuse box to do it and install the diode in the wire.

SO, now you have dim highbeams in DRL mode and when you turn on the headlights, the DRL's turn off. And if it gets dark enough that you happen to notice the highbeam indicator is slightly illuminated, (cant see it during the day) then perhaps it is time you turned on your headlights.

I will post up the steps with pics and a part# for the diode when I finish.
UPDATE: 15 amp diode is a bit hard to find in stock locally, I have one coming, should be here next week sometime, around $7, will post part# and order info when I am done.

Re: Simple and cheap DRL using the highbeams

Posted: Thu Dec 06, 2007 7:58 pm
by TardisDeli
Hi Eric, Wow, your brain is on hyperdrive. Cool idea.

The Diodes can be bought at RP Electronics, just off Lougheed Highway on Rosser (1 block ish west of Willingdon, near Canadian Tire). http://www.rpelectronics.com They are very friendly, even with people who only half know what they are doing.

Cheers, Jay and Christine of the TardisDeli

Re: Simple and cheap DRL using the highbeams

Posted: Thu Dec 06, 2007 8:41 pm
by EricN
They said they dont carry any diodes with a maximum forward current of anything more than an amp. I looked at their online catalogue too and they dont show much. The fuse is 15amp and as far as I can tell, it is the only thing on that circuit. I have a 16amp/1000v one coming, that way if I have a short that blows the fuse, the diode should survive, I hope.

Re: Simple and cheap DRL using the highbeams

Posted: Fri Dec 07, 2007 10:08 pm
by EricN
Could someone who is very non-electrically inclined look at my diagram and tell me if it looks easy enough to them?
http://wikrad.com/delica/index.cgi?dayt ... lights_drl

***I added directions for wiring up just the lowbeams as a DRL as cheap/simpler option for those that so desire.*****

Re: Simple and cheap DRL **Warning, Please read update**

Posted: Wed Dec 12, 2007 9:32 pm
by EricN
I finally got the diode in and hooked it all up. Works good EXCEPT, highbeams energize the ignition. I cant believe I didn't see it in the schematics staring me square in the face. Completely stupid move on my part but that is what I get for rushing into it.
Thankfully, it is a simple fix, just need another diode, but this one can be an easy to find cheapie. I will correct the diagram in the wiki too and post a part # for both diodes.
Sorry if anyone got screwed up from this.

Re: Simple and cheap DRL using the highbeams

Posted: Thu Dec 13, 2007 12:23 am
by Delicaman
Did you guys ever think of wiring into the oil pressure sender wire thats in the main bundle that comes up through the floor behind the cool box? Its the yellow wire with the single silver dot. Lights come on when your engine is running. Just like it says in the instructions. I've been doing this on the last three vehicles. Its the Canadian tire DRL for $24.95. A lot less work guys..

Cheers,

Benn

Re: Simple and cheap DRL using the highbeams

Posted: Thu Dec 13, 2007 1:00 am
by EricN
For cheap and easy look no further than the bottom of the wiki page on DRL install (although I effed that one up too and had to go fix it). I am going more for tech and cool factor. Anyone can have low beam DRL but that is yesterdays news. Dim high beam DRL is what all the cool kids are doing.

Re: Simple and cheap DRL using the highbeams

Posted: Sun Dec 16, 2007 7:13 pm
by Green1
not a fan of high beam DRLs... but I'm quite impressed with what I rigged up using a modified version of the front parking lights... see this post for more information