low beam on with hi
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=84611
Printed Date: May 11, 2025 at 11:17 PM
Topic: low beam on with hi
Posted By: silverado42000
Subject: low beam on with hi
Date Posted: October 25, 2006 at 10:53 AM
hey, i have a 00 Silverado 2500 LS and i need the wiring diagram from the headlights so i can install a relay so when i turn on my high beams my low beams and my fog lights stay on, i would like to be able to do this from the fuse box is possiable to keep it looking stock since i have blank relay spots in the fuse box under the hood. thanks in advance ------------- 
Replies:
Posted By: ff-mike
Date Posted: October 27, 2006 at 12:22 PM
Kind of contradictory to run fog lamps (for use in adverse weather to avoid glare) and high-beams (not to be used in adverse weather because of glare) simultaneously. Also not legal in many areas- too much candlepower.
Posted By: silverado42000
Date Posted: October 30, 2006 at 11:06 AM
well i dont plan on haveing them on all the time, just when im on the road and no other cars are infront of me i like to see easly so why not do that by having all the lights come on with the brights, plus for pics at night i think it looks better -------------
Posted By: kymadan
Date Posted: October 30, 2006 at 11:56 AM
With it not being legal in some areas, it might be hard to get an answer to this.
Posted By: silverado42000
Date Posted: October 30, 2006 at 4:30 PM
how is this not legal, they sell kits for it, im just cheap and rather do it myself, just dont know how to go about doing this, weather i should just tap into the regular lights and use a relay or what -------------
Posted By: ff-mike
Date Posted: October 30, 2006 at 4:59 PM
#1 FMVSS 108 states that you can only have 4 driving /fog /head /aux lamps on at the same time.
#2 Most states have an adopted or stricter version of this law.
The newer GM trucks have all of the lighting controlled by the BCM, and what works on my 98 may cause problems with yours.
Posted By: silverado42000
Date Posted: October 30, 2006 at 5:14 PM
well if thats the case then i will just have the highs and lows on with out the fogs -------------
Posted By: bballguy162006
Date Posted: November 22, 2006 at 5:17 PM
Before I get started I just want to say: no offense to anybody.... Why does everybody care so much???? I guess poicemen are on this site? I would understand if they would inform you that it is illegal (assuming you are going to use it on the highway, but who needs to know :-) ) and then tell you how. Now if you said that you want to use it to blind people while you were driving I would understand why nobody would tell you how, but this is not the case. People ask how to install neons inside and outside of their car (illegal), they ask how to install aftermarket HID kits (illegal)....... Why does this matter? I don't know silverado42000: If I knew I would tell you. My best guess would be to use relays like you said, that should work. I don't know if this helped at all, but I was just frustrated at people killing your idea. You should do it if you want, it's your car and if for some reason you use it irresponsibly and get in trouble, that will be your fault and you will be responsible for it. Which is the same for pretty much anything else aftermarket that people do to their car.
Posted By: Mad Scientists
Date Posted: November 24, 2006 at 11:29 AM
Why should we care?.. I'll start by addressing your closing comment.. "if for some reason you use it irresponsibly and get in trouble, that will be your fault and you will be responsible for it" Unfortunately, that doesn't seem to be how it works; at least in the US where I live. We seem to live in a society of 'it's not my fault'. We recently had someone convicted of murder in the first here.. 20y/o shot and killed a retired schoolteacher. When it came time to decide if he would live or die, we got to hear about how he had a bad childhood, how he wasn't trying to kill her, just shoot the mirror on her car and he was startled when she honked the horn... over and over, just the same verse of 'it's not his fault'. He's serving life without possibility of parole.. she's still dead. What does this have to do with wiring so all the lights stay on?.. nothing much other then I'd be surprised if someone got busted for something they did and they _didn't_ try to place the blame elsewhere. It does happen.. I saw it recently in the news; but it's not common. To address the lighting issues.. first off, it _does_ have to be mentioned that what the OP is asking is illegal, at least in some areas. I don't see a problem with asking the OP if they've checked with local law enforcement to see if it is or not. Secondly, it's not a very interesting question.. as we don't get paid for doing this (at least not directly.. I'm at work 'taking a break') it's not something that someone might be willing to spend the time to research. As noted earlier in the thread, cars are getting complicated and this question would require someone to look up a wiring diagram to see how things are set up.. now, I have done that in the past (looked up something for someone) but it was mainly because they wized me off with their crying.. which ties in with my next point.. People want the easy answers.. they don't want to hear 'calculate the value of the resistor using Vf and If and Ohms Law'.. they want to hear 'use a 270k Ohm resistor'. How many requests do we get here for LED resistor values and 'How do I get 5v from12v?'.. I don't know that this request is going to be an easy answer... And lastly.. Professionalism. You yourself alluded to this when you talked about not giving answers if you knew that the information given would be used for illegal purposes. It makes all of us here look bad when someone goes thumping through a residential neighborhood at 3am.. when someone uses the 'spit and twist' method of connecting wires together... it makes all of us look bad. When someone uses a R/S for an auto trans in a manual trans car, and things go horribly wrong, it makes all of us look bad. My reasons for not responding to this thread are; I don't know the information required to help, I don't know how much running all the lights will help see at night (I think the OP would be better served with getting some **good** aftermarket lighting) and I have my concerns with running both high and low at the same time.. the heat generated might do bad things to the reflector housing. Now.. if the OP would still like some help with simulating an ignition system for a senior project, I'd be glad to help.. and I've got some good ideas if they are interested in playing with ICs. As always.. no offense to anyone.. hope all had a good Thanksgiving (if that's something you celebrate) Jim
Posted By: Mad Scientists
Date Posted: November 24, 2006 at 2:17 PM
Having said all that, the body control module does control some aspects of the lighting... specifically the fog lights. The headlights are powered through a relay and controlled on the ground side by the dimmer switch. The fog light switch sends a signal to the BCM which sends a signal to a fog light relay when necessary (when the lows are on). The BCM also controls the DRLs.. while anything is possible, short of having the programming for the BCM (with regards to the lighting controls) the only way I see to accomplish what you want (all lights on) is through trial and error, with no promises as to what might happen with you start jumping circuits around. I don't know what kind of error messages you might generate when you try this.. you mentioned that people sell kits to do this.. if you link to one of these kits (hopefully with install info) I might have a better idea of how they are accomplishing it. Do you have the ambient sensor in the center of your dashboard?.. I'm assuming this vehicle is a 2000 Chevy Silverado 2500. Detailed information about vehicles can be obtained by searching for Alldata DIY.. it's a subscription service, but it includes information at the repair shop level.. Jim
Posted By: triplejackinga
Date Posted: November 27, 2006 at 2:44 PM
You can get this 'kit' for $20 from Stylin Concepts. ------------- *****************************
TripleJack
*****************************
Posted By: Mad Scientists
Date Posted: November 27, 2006 at 4:26 PM
Hmm.. that's one way of doing it.. it's not my way, but it's one way. They seem to be running the low beams from the high beam circuit when the high beams are on.. the 'kit' is a box with two wires on it.. one wire goes to the high beam wire, one wire goes to the low beam wire. Looks like a diode to me.. I'd be surprised if it was more complex then that. They do include the scotch blocks to make the connections though.. that's gotta count for something. No mention of the voltage drop involved with the diodes (assuming they're using them), no mention of what to do if it throws a code, and no mention of what adding the low beam current draw to the high beam circuit is going to do to the fuses/wiring/switchgear. Jim
Posted By: silverado42000
Date Posted: November 27, 2006 at 6:20 PM
dont remember if i said it before but thats what i was talking about, but i was wanting to do it a different way, right from the fuse box, put a relay on the low beams so when the highs are on they turn on the lows again, i just dont know how to do it, since its controlled threw the ground on the switch, i figured out this much, truck off, lights see 0v, with the truck on both highs and lows see 12v, then the ground is controlled threw the light switch. -------------
Posted By: conair
Date Posted: December 01, 2006 at 2:28 PM
Don't know if this might help, but on every car i can think of, whenever I use the high-beams, the moment the stalk on the steering column is moved to turn on the h/b's and before it springs back, both h/b's and l/b's are engaged at the same time. I am sure this overlap is to prevent a moment of darkness between low and high. A little reverse engineering of the circuit, or studying of the schematic should be enlightening, I would think. In any case, let us know how it goes, illegal or not, the more knowledge related to mobile electronics compiled here the better off we all are.
Posted By: silverado42000
Date Posted: December 01, 2006 at 2:46 PM
never thought about that, but yes i do know that they both come on, i could take apart the column and find the switch and do some wire crossing or somthing, but i would rather use a schematic it would be better i think to draw it out first, found out that its much easier to work on big wiring projects when you have it laied out on paper already. if anyone knows where i can find a schematic of one, or even better one of the entire truck i would love it, but i would ask it be free as i am broke at the moment.
And as for all the people saying that it is illegal, well its illegal to have you brights on when a cars coming at you in the first place, just having the lows on with them wouldnt change that, and ive always turned my lights to low when cars are coming, i just want the highs and lows on because when your on a dark dirt road and turn on the brights, you only see far away, and when there are deer and deep ditches and potholes everywhere, its better and safer to have the up close view and to be able to see up ahead, as in my case, if a river has flooded over road and since your driving with the lows to see all the little holes and trying to keep control it doesnt just come up on you, Thank god for 4x4. -------------
Posted By: king kong
Date Posted: December 25, 2006 at 7:02 PM
How to wire the lo beam to stay on when the high beam is on
1) find the feed for your hi/lo switch
2) find the feed from your hi/low switch to the low beam
3) scotch lock both feeds
result low is on at same time as high all for the cost of a scotch lock I've done this mod to all the cars I've owned without a problem.
N.B this is an old rally drivers trick
Posted By: king kong
Date Posted: December 25, 2006 at 9:10 PM
[B]before[/B]
high/low switch
______ low beam
from + ________
main light ______ high beam
switch
[B]After[/B]
high/low switch
_________________ low beam
from +_________
main light __________ high beam
switch
when the hi/lo switch wired in this way the low beam stays on when the high beam is on
Posted By: ff-mike
Date Posted: December 28, 2006 at 10:34 AM
I completely agree with the reasons why to do this.
Issue #1 is that DOT spec lights are garbage to begin with. This is made worse when the auto makers trade functionality for fashionability. The more you stray from a round headlight, the worse it gets
Issue #2 is cost to the auto maker. They use a wire size that is IMHO too small for the lamp- this will have a detrimental effect on the lighting also as the voltage will be lower. Bridging the beams together will only make this worse as the ground wire will be carrying twice the current, and therefore have twice the voltage drop. At 12.5 vdc, you headlamp output is only 92% of the lamps spec, at 12.2vdc that will drop down to 85%
Fixes
Issue #1 cannot be fixed legally for cheap. The only way to do it is to replace the entire assembly with something that is DOT approved. I have seen custom assemblies done using Hella 90mm low beams and high beams placed into aftermarket assemblies. Another possibility is tpo scavenge an HID assembly from a sister model if available
Issue #2 is a little easier to do, but may be complicated by the BCM and how in depth it is integrated into the system. What you would do is replace the headlamps with relays, and use some nice thick wiring for battery - relay- headlamp wiring. This will minimize the wire length and voltage loss due to length and size. My Jeep went from 12.4V across the filament to 13.1 volts- which comes out to about 35% brighter. You still are; however, subject to issue #1- you just have more light available to scatter haphazardly
What would I do? I would upgrade the wiring, and get some real auxilary lighting. OEM fog and driving lamps are worthless (form before function again). From what you have posted, I would probably get a decent set of driving lamps (not from local parts shop or WallyWorld) and aim them a little on the low side for up close usage with the high beams. Low beams can be supplemented with auxilary low beams to help out on that end. Another option would be to get a pair of Hella Vision replacement headlamps and mount/aim normally, and piggyback them off of the headlamps.
Posted By: silverado42000
Date Posted: December 29, 2006 at 4:08 PM
well i was lookin on another forum and i found out a way, since on the 99-02 Silverados the lights are controled threw the ground so all i did was under the fuse box took the wires for the lows and ran them streight to ground, its alot better now, as for wire size mine are thick enough for what bulbs i have in them, getting 13.9 at them so i dont think it would help much to upgrade the wiring, thinking about it tho -------------
Posted By: distantimports
Date Posted: December 29, 2006 at 5:11 PM
As for reading the whole thread I would just like to say that I have had really good luck with the painless wireing harnesses. Along with I know that you can use a couple of relays but I have just done this at the lights not at the fuse box. It much easier at the light bulbs because you will not have to run extra wires into the cab of your truck. I own a 1990 GMC and i love my conversion. I also purchased the H4 conversion with some aftermarket projectors and I really have no problem at night. I am not familiar with all state laws but I do know that in Washington state the law stated above about only having 4 foward facing lights is true. But how ever I have just talked to my eye doctor and had him write me a perscription for have another set of lights because I have a hard time at night seeing and in the area that I live in there is a ton of Animals and wildlife all the time in the road and i am tired of repacing fenders and hoods etc. This is the link to Painless wireing but check them out cause they show some detailed pics of there harness and you might get some ideas. https://www.painlesswiring.com/webcatalog/2007Catalog/catview.php?SearchField=20 ------------- Mitch
Distant Imports
Owner
Posted By: suburban boy
Date Posted: December 31, 2006 at 8:49 PM
okay...after all that arguing about if its legal or not.... PerformanceProducts.com sells a module that cna do all that for you.....i ahve it installed on mine 02 suburban ------------- Suburban boy
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