Question: High and Low beams active at the same time
 

Hello Community, I’m currently attempting to retrofit my GSL-SE to use Projectors :biggrin: Problem is that they are low beam only. I have a set of fog lights I would like to triger on when turning on the "high beam" on my factory switch. Problem with that, low beams (Projectors) would turn off when I switch on the high beam(Fog lamps):dunno:. I currently have the Black Dragon relay kit installed and thought of adding in a diode to this equation so when I turn on my high beam I can keep the low beam on as well. What kind of diode do I use? Any other Ideas? Thank you!!

You'd need to find out the current draw of your relay's coil,and then pick a diode with at least that high (I'd go over by 50%, myself) of a spec for "continuous forward current" & a minimum of 25V or so "reverse voltage."

This will help a lot:

http://www.kennethkuhn.com/students/...ifications.pdf

As an E.Eng, I'll toss my thoughts in.

So you want your low beams on for both high and low operation, but on high beams, also toggle on a set of fog lights. Simple enough, you should be able to use a diode for this.

What I would do personally is use a relay on the fog lights. We can get fancy, since you no longer will be using the high beam relay from BD. Connect the power wire for high beams after the relay in the BD harness to your fog lights. Probably cleaner to splice the wire near the relays and then bring it down to your fog lights, instead of dealing with it at the lamp connector end. This would let the stock low beam signal turn on the projectors, while high beam would turn on the fogs.

Now we want to keep the projectors on when the fogs are on. You are right in wanting a diode for this purpose. Lets place the diode in the BD harness between the low and high pin 85. We will place it in such a way that current can flow from the stock high beam signal, to the stock low beam signal. Diodes are marked with a line on one side of their body. Think of this as a wall. Current flowing into the lead on the lined side is blocked, while current flowing into the other lead is permitted to pass through. Connect the line side lead to the low beam pin 85 and the other lead to the high side pin 85. (this is assuming BD used pin 85 for connection to the stock harness's high and low and pin 86 for ground)

As for which diode to select, many will be good enough for your application. I personally use 1N5408, which are complete overkill, but I have a metric assload of them. Any of the 1N4001 to 1N4007 will work as well. Remember we don't need a high forward current as we are just using it to toggle a relay.

Since you are in the USA, lets use radioshack. Any of these will work:
http://www.radioshack.com/product/in...ductId=2062578
http://www.radioshack.com/product/in...ductId=2036270
http://www.radioshack.com/product/in...ductId=2036269
http://www.radioshack.com/product/in...ductId=2049728
http://www.radioshack.com/product/in...ductId=2036268
http://www.radioshack.com/product/in...ductId=2062579

I'd go with something in the 1N540X range, as they are 3A versus 1A and I like having large design tolerances. If you want, go find a diode, post it up here and I'll let you know if it will work.

:scratch:

Lined end = cathode; unlined end = anode
Diode conducts when forward biased: that is, when cathode is more negative than anode
Current (electron) flow is from negative to positive potentials
Therefore, current flows in through the lined end.

:scratch:

Would the diode get damaged if I give it a trial and error in direction in which path the current flows?? Once again thank you both for the PDF and the wiring ideas.

You are using electron flow not conventional current flow thinking. Nearly all electronics and electrical engineers in North America will use conventional current flow. Textbooks are written in both and while it doesn't really change anything, you have to be consistent. Most higher level books will still use conventional.

Conventional Current assumes that current flows out of the positive terminal, through the circuit and into the negative terminal of the source. This was the convention chosen during the discovery of electricity. They were wrong!

Electron Flow is what actually happens and electrons flow out of the negative terminal, through the circuit and into the positive terminal of the source.

Attachment 758647
Think of the arrow as the current flow direction.

Just do as I said. Lined side to the low beam 85, unlined lead to the high beam 85.

Yeah, I'm not an electrical engineer, but I've done quite a bit of controller modding and whatnot in the past few years. Whenever I read about electric currents and how electron flow is actually the opposite of what you'd expect, it makes my brain hurt a little.

Anyway, can this be archived? If I ever want to install foglights in the future, I'd love to be able to easily reference this thread.

Maybe they teach conventional current now, but when I was learning electronics as a kid, all the time I went through high school and college, through to when I later taught comms systems & crypto maintenance in the service (MCCES 29 Palms) in the 80's... we used electron current for any analog situation. We learned conventional current (aka "hole flow" back in those days) from a standpoint of following the charges inside semiconductors, and that's about it - - outside of learning about the goof-up in choosing names for positive and negative in the early history of the science.

I started in with electronics when I was 8 years old, just as tubes were saying their final goodbye in the very late 60's... and tubes were sheer electron flow devices. Try explaining a CRT from a standpoint of conventional current! :lol:

Way to make me feel obsolete, Sgt F! :(

Next thing you know, you'll tell me that the bubbles going up are more important than the water they move through!

This wouldn't be a smart way to wire up foglights in addition to the factory high/low. This is more a special case with a projector combined high/low and fog.
Tubes are always fun. I have a soft spot for the old tech and most people consider me crazy when I start wire wrapping instead of just spinning off a pcb. For anyone that wants to see a really sweet tube style appliance, look up Mercury Arc Rectifiers. Those things are both beautiful and scary!

To be honest, even the old textbooks (70/80s) I've read use conventional. They usually note that there is a difference in convention in the preface but default to conventional. It really is a matter of whatever you are comfortable with. One can understand and theorize the same principals with either method. I would imagine right hand rules for electromagnetics start getting a bit reversed though.

I figured as much, but by the time I thought about that it was too late for me to edit my post. In that case, what would be the best way to do that, besides taking the easy route and installing a rocker switch just for the foglights? I'm really curious.

[edit] haha wow, I think you screwed up Edit and Quote up there, Sgt Fox.

Best way would be to use the low beam to trigger a relay. Stock low beam to pin 85, pin 86 to ground, fused 12VDC to pin 30 and fog lights to pin 87.

What projectors are you using? I assume there not bixenon since you need a high beam.

Thank you guys for the tips!
I went to my local Radio Shack and purchased "3-Amp Barrel Diodes
Model: 1N5404" http://www.radioshack.com/product/in...ductId=2062579
Works Perfect! :icon_tup:

I ran into a small problem because the black dragon kit doesn't use bosh style relays, they are 4 pin and UNLABELED! So I pulled out my trusty multimeter and took my time. After I had it sorted out I did the following....

I disconnected my high beam power cable from the Black Dragon Harness to the head light and connected my fog lights to that connection.
Then I placed my relays side by side and got the diode and bent it in a U-shape and bridged the relays with current coming from the high beam to the low beam trigger pins and VOLA!!



I Will be using Lexus AFS RX330/350 Projectors with a clear lens to sharpen up the cutoff line.

This is the relay style Black Dragon uses.http://img.photobucket.com/albums/v2...Cars/Relay.jpg

These are current pictures with sealed beam halogen lights, projectors not installed yet:icon_tup:
Low beam only
http://img.photobucket.com/albums/v2...s/IMAG0682.jpg

Low beam with fog lights active by high beam switch thanks to the relays and diode.
http://img.photobucket.com/albums/v2...s/IMAG0683.jpg

During the day
http://img.photobucket.com/albums/v2...s/IMAG0676.jpg

At night
http://img.photobucket.com/albums/v2...s/IMAG0677.jpg