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How To: Headlight All On Mod - Discussion

344K views 678 replies 319 participants last post by  handirifle 
#1 · (Edited)
This is a write-up for how to make your low beams and/or fog lights stay on when you switch to high beams...This mod costs all of about $1 and should take no more then 15 minutes..its very very easy and use's the trucks own built in fusses and relays. Credit for this goes to Will from duramax diesels...i just made some additions and modifications..

All you need is a set of diodes that you can get from your local Radio Shack. The part number that I used was 1N4004. I have read that 4001,4002,4003 and 4004 will all work. These diodes come in a 2 pack and cost $.97.

You will do this mod under the hood at the fuse block on the drivers side of the truck. Make sure that the truck is off before reaching in there. You shouldn't need to unhook the batteries or anything like that.

On the bottom of the relays is the numbers for the different pins. You will be using the 85 pin for these mods. Also, on the bottom of the lid of the fuse block is a diagram showing the numbers of the pins along with which relay goes where. The 3 relays that are used are in the lower left hand corner of the fuse block

Hi-lows on at the same time.
You will need to connect the 85 pin of the low beams relay to the 85 pin on the hi beams relay. Make sure that the "bottle cap (or end with the stripe)" is going towards the hi beam relay. You can either wrap the wire around the metal pin or slide it into the hole that the pin goes into. Either will work.

Hi-fog on at the same time.
For some reason GM decided that when your high beams are on, your fog lights don't need to be(actually i believe this is a law) . Well I like my fog lights on adding more light. With the hi beams on adding a lot of light, then the fog lights on adding more light can't be a bad thing right?

To do this you will need to connect the 85 pin of the fog lights to the 85 pin of the hi beams. Make sure that the "bottle cap (or striped end)" is going towards the hi beam relay. Again you can either wrap the wire around the pin or push it into the hole that the pin goes into. If you are doing the lows plus the fogs it can be a little tight on the 85 pin of the hi beam pin. For this I wrapped one diode around the pin and the other got pushed into the hole with the pin(i pushed both into the slot...they fit you just need to push down hard on the relay) . You will still have control of your fog lights on low by switch but by doing this the fog lights will always be on with hi beams.

This Mod works perfectly with HID's as well as regular bulbs.

The pic shows how I have it wired. Sorry for the poor picture but hopefully the labels will help better explain things.



 
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#5 ·
thanks brain... i noticed most guys over here didn't know about it

Nice.. I should do that I hate having fog lights off. I would like to just make them on 24/7. I am tired of hitting the button. I light them on all day with markers.. And same thing no matter what light is on they should be. They look awsome.
thats possible....uh..if you ran a diode drom the daytime running light relay pin 85 going to the foglight relay then whenever they came on the fogs would be on..






Sweet...thanks seth
 
#3 ·
Nice.. I should do that I hate having fog lights off. I would like to just make them on 24/7. I am tired of hitting the button. I light them on all day with markers.. And same thing no matter what light is on they should be. They look awsome.
 
#6 ·
Sweet Im saviing that.. Radio shack on lunch break and i'll go out on my boring day at work and see if I can't set something on fire haha
 
#8 ·
dont worry about that...you only need the one on the left...ask the radio shack dude for diodes then go to the drawer and look for number IN4004...if they dont have those 4001,4002,4003 will work as well
 
#9 ·
I did this on my other chevvy and it's gret just havent done it on the d-max YET...acutally now that this thread made me think about it I'm gonna go do it tonight...with daylight saving BS it's almost dark at 5 when I leave work so I will get plenty of use
 
#11 ·
thanks..yea i knew about it for a while but thought it was really complicated...after i did it i was like. man that was easy lol
 
#12 ·
I've been looking for this mod for a while. Great job! I'm hooking mine up tonight. Thanks!
 
#14 ·
awesome write up. i will be buying the parts tonight. anyone help me with printing this out? for some reason my computer here at work won't let me shrink the page so it all fits widthwise on the print out?
 
#16 ·
good idea. never even crossed my mind. thanks. lol
 
#19 ·
yea man...ill take .99 over $60 any day

Hey Beech, Great info. Thanks for waiting until AFTER I spent $50 for the relay. But now I can do this to the wife's Suburban.
sorry man :( ...i really thought it was more well know its all over the other sites..

did you install it yet? if not maybe you can send it back or put it on ebay?
 
#18 ·
Hey Beech, Great info. Thanks for waiting until AFTER I spent $50 for the relay. But now I can do this to the wife's Suburban.
 
#20 ·
So, if i flick on my brights and have both diodes in place, will my fogs, lows, and highs all be on?
 
#22 ·
yessir....even turn on the little indicator on the dash to tell you your fogs are on:D

Ya been on for a couple months now, OH well. It's only money.

Compared to Obama I haven't spent much. Gotta keep it in perspective!
hahaha man i like you more with every post:drink
 
#23 ·
Thanks, is it bad that i spend all day on this forum?
 
#26 ·
Any ill side effects of this for the lights or truck other than fines associated with having all 6 lights on LOL? Not for the on coming traffic LOL
 
#28 ·
nope no ill side effects at all...each light set has its own direct power and the trucks own relays are telling them to turn on...


but like you said oncoming traffic might hate you lol
 
#27 ·
Just finished the mod. Its still bright out and the lights are still very much visible. Cant wait to do it at night.:rockin:rockin
 
#35 ·
by dims you mean daytime running lights? if so yes....same if you hook em to the highs you wont need to press the button

I just looked at my fusebox on my 2001 LB7 and I don't have seperate high and low beam relays. I guess now I'll have to go out and get a newer truck!
hmm....never saw an 01 but i do know they changed a buncha stuff after 02
 
#30 ·
I just looked at my fusebox on my 2001 LB7 and I don't have seperate high and low beam relays. I guess now I'll have to go out and get a newer truck!
 
#484 ·
all new 2012 LML have seperate relays....:poke[1]::drink:D
go get you 1 bud..:thumb
 
#31 ·
Yeah or just buy a relay and wire your highs and lows together...the DRL kit i used was $10. I mostly bought it just for the relay. I didnt have a radio shack around and didnt want to deal with trying to find one elsewhere.
 
#32 ·
I love the fog lights, I'm gonna get to this mod eventually.

I always get hi beams flashed at me when my fog lights are on at night though, I guess cause with the 33's I sit pretty high, and they shine right into cars.
 
#33 ·
yeah try 37's my fogs and los hit them right in the eyes even in suv's so I get bright lighted...I'm gonna do this mod and run all HID's and see what they think then
 
#46 ·
i know what you mean, i get people flashing at me every night! they really dont like it when i flash back with 8 bulbs :D I cant wait to do the HID upgrades and see what happens next
of course the worst is when they see you shut your hi beams off and still try to get you to turn em down...Theres only 2 settings!! Bright and BRIGHTER:cool: lol
 
#34 ·
Man I cant wait for my HIDS too Now Seth999 you know yours is under the dash right
 
#37 ·
oh haha never heard em called dims before but yea just have the side of the diode with the stripe pointing to the low beams
 
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