Turning on only your Fog Lights....?

[diablo2184]

hey all,

i am new to this site, as well as TrailVoy. i have searched and came across the quad mod, DRL killer, and capacitor mod on the forums. But i have not found one to be able to run the fog lights at any time i want, with or without ignition on.

i plan to do the DRL killer so i don't have those lights on all the time. but i would like to run my fogs by themselves when id like to. has anyone else done this? how do i need to wire the OEM fogs?

thank you all

 

[Robbabob]

Welcome to the Nation!

 

[Mounce]

So you don't have oem fog lights?

I can manually turn my headlights off and turn on the fog lights but it makes the parking lights come on.

Btw, trailvoy is a wasteland now and can only be useful for it's older content that the guys here left behind. Also, Welcome to GMTNation!

 

[diablo2184]

thank you, Rob.

Mounce, I have OEM fogs but I cannot run them by themselves. other lights do turn on when i push the Fog button. I want to bypass that so i can run the fogs without parking lights or if i have no "ignition" on. i did it with my other car, so i was just curious if someone has bypassed the computer on this truck.

 

[Mounce]

I haven't heard of anyone doing it. I guess you could always run a separate circuit to the bulbs and have a dedicated switch to turn them on and off.

 

[dmanns67]

So you have OE fogs and want to be able to hit the fog light button to turn them on anytime you want without having the key in the ignition? Any particular reason you want them to function like that?

Dont waste your time on TV. Welcome to the Nation

 

[Mark20]

Welcome to the Nation.

 

[Blckshdw]

The headlight control module ties into the body control module under the back seat, then triggers the necessary relays to activate the designated lights. The easiest method to accomplish what you're wanting to do is run new wiring, through a relay, to a separate switch in the location of your choice.

Unless you know someone who can reprogram your BCM, and won't charge you an arm and a leg.

Edit: Or, if you don't mind cutting up your stock wiring, cut the wire from the fog light button that signals the BCM, and run THAT to activate your new relay harness. That would do the trick.

 

[diablo2184]

So you have OE fogs and want to be able to hit the fog light button to turn them on anytime you want without having the key in the ignition? Any particular reason you want them to function like that?

Dont waste your time on TV. Welcome to the Nation

I guess I am just weird like that. All the other cars i have owned, another forum member has so i followed the DIY. I like running the fogs in low light situations before dark, instead of headlights. and with my other vehicles, when you switch the high beams on, the fogs would shut off. so for those cars, they would wire it so the fogs can always be on and it would just be independent from the other lighting (i know we have the quad mod with fogs). just a thing i guess.... and thank you.

Welcome to the Nation.

thanks!

The headlight control module ties into the body control module under the back seat, then triggers the necessary relays to activate the designated lights. The easiest method to accomplish what you're wanting to do is run new wiring, through a relay, to a separate switch in the location of your choice.

Unless you know someone who can reprogram your BCM, and won't charge you an arm and a leg.

Edit: Or, if you don't mind cutting up your stock wiring, cut the wire from the fog light button that signals the BCM, and run THAT to activate your new relay harness. That would do the trick.

so if i go to the dealer, they can reprogram this to do it?
i dont mind tapping into the OEM harness and grounding the relay and running it to the switch. but which wire is it? im not the best figuring all this stuff out. i can do it once its been shown or explained.

 

[Mounce]

Idk if a dealer would do it or not but if they did it'd be at a decent fee.

Mooseman (a member here) has a free download for service manuals that include wiring diagrams if you want to try to look over them yourself.

 

[diablo2184]

well i may have some contacts still at a local chevy dealer. but i wasnt sure if their scanner can do that type of thing

 

[Mounce]

It would have to be a GM Tech2 scanner.

-Now I see you said "their scanner" I read it as "a scanner" so yes, their scanner will do it.

 

[BlazingTrails]

http://pages.ebay.com/link/?nav=item.view&id=221454148594&alt=web

 

[diablo2184]

It would have to be a GM Tech2 scanner.

-Now I see you said "their scanner" I read it as "a scanner" so yes, their scanner will do it.

yeah the Tech2, i havent been there in a while, so i thought it would be a Tech3 lol

 

[MAY03LT]

Sounds like a cool project. Probably would have to eliminate the bcm altogether so it doesn't turn on the park lights. The tough part will be using the factory switch. When you press the fog button it just pulses the signal to the bcm. If there was a way to take a pulsed signal input and turn it into a latched output for the relay control (ground) it could work. It would also have to unlatch on a second pulse.

 

[diablo2184]

Ok so what if I tap into the fog light harness with a relay and then run it into the OEM switch? Does that make sense? Am I understanding the wiring correctly?

 

[swede]

A dealer or anybody else with a tech2 can NOT program a BCM to do what you want done. Only one who would be able to that would be General Motor. And I'm pretty sure they will not write any new code / software for a BCM that will turn on the fogs like you want. Each software that are programed in to a module is developed for that module. E. i if the modules partnumber don't match the p/n in the software it won't download to the module. It's very complicated system

 

[MAY03LT]

From looking at the schematic it looks like everything is already there at the fog relay except for the control (arrow). If you can get a ground there, they will work even with key off. The problem with using the factory switch is that it doesn't lock in when you push it. The bcm "sees" that you push and it provides a constant ground to the relay.

The only times I have messed with pulsed/latched ins/outs were when doing custom alarm installs with AUX outputs. If I had to guess I would think that someone makes some kind of wacky adapter for converting pulsed to latched.

 

[diablo2184]

Damn. Ok.

Hopefully we can come up with a solution....

 

[diablo2184]

Any of these?

http://www.the12volt.com/relays/page5.asp#lsp

 

[oleblue02]

So you don't have oem fog lights?

I can manually turn my headlights off and turn on the fog lights but it makes the parking lights come on.

Btw, trailvoy is a wasteland now and can only be useful for it's older content that the guys here left behind. Also, Welcome to GMTNation!

This is what I do.

 

[DAlastDON]

If you want just the fog lights on with nothing else. From littleblazers experience in doing the same thing, you gotta take the logic away from the BCM for no parking/dash lights coming on. Can be done with a latched relay setup.

Utilizing MAY03LT's schematic...

Fog light switch sends a ground pulse with every push. Cut the ORN(192/0.35) wire at the BCM. On the schematic below connect that to the pin 30 on the second relay from the right(bright green wire in schematic). That will serve as the switch in the below schematic. Then cut the DRK GRN/WHT(1337/0.35) wire at BCM. That will then connect to pin 30(dark yellow in schematic) on the far right relay in the below schematic. Every time the fog light switch is pressed it will toggle the fog lights off/on with a ground pulse.

OR simply install a toggle switch the sends a ground signal to the factory fog light relay. Cut the DRK GRN/WHT(1337/0.35) at the BCM and tie the toggle switch to it. This will turn the fog lights on weather the key is turned on or not. If you want to set it up to shut the fog lights off when the key is turned off the use a Normally Open(NO) relay with a switched 12v input to the relay coil to interrupt the ground from the toggle switch when the key is turned off.


Edit. That schematic above outputs 12v. You want it to output a ground. I will look for a schematic that outputs a ground instead. Other wise another relay can be used to change the logic to a ground output instead.

 

[Harpo]

When i installed my HID:s i did it by shifting the wires, put the lowbeam harness at the fogs.

By doing this i have fogs as drl:s and when it get darker the parking lights turns on and that triggers a relay that turn on my hid lowbeam. By doing this your fogs will always be on and your fog switch useless but you can turn of the fogs by turning the knob to parkinglight only, that will shut the fogs of because they are really your lows. The HID:s will be on lowbeam still because they are wired via a relay triggered by the parkinglights.


Wow, hope thats making any sence to you,,,,,but it works.


TB:s sold here in Sweden has fogs for DRL as standard, if thats is another program in the bcm or if it's done by the different lightswitch we have here i don't know. But if it's in the bcm it would be possible to do.


My TB is a US import so it's the same you have.


Edit: I just reread your post.
This isn't really solving your exact wishes, but it's an alternative for you and others.

 

[DAlastDON]

This covers how utilizing a microchip.

http://www.electronicecircuits.com/electronic-circuits/momentary-push-button-soft-latching-toggle-on-off-switch-circuit

 

[diablo2184]

The headlight control module ties into the body control module under the back seat, then triggers the necessary relays to activate the designated lights. The easiest method to accomplish what you're wanting to do is run new wiring, through a relay, to a separate switch in the location of your choice.

Unless you know someone who can reprogram your BCM, and won't charge you an arm and a leg.

Edit: Or, if you don't mind cutting up your stock wiring, cut the wire from the fog light button that signals the BCM, and run THAT to activate your new relay harness. That would do the trick.

can someone with a tech2 reprogram the BCM to do all of the lighting mods? quad mod with fogs, DRL kill, etc?

 

[Blckshdw]

I have no idea how complicated, or possible, all that is. And if it IS possible, how long it would take, or how much you'd get charged for it.

 

[diablo2184]

well i have access to one, but if its not that easy then i guess i will continue to research wiring to get the highs how i want. lol

 

[Blckshdw]

Having access to one is only the first step. Either you, or whoever owns it, needs to know how to do custom programming on it. Downside to tinkering with one of the vehicle's computer systems is, if you do something wrong, you could lose communication with other modules in the truck, or even lose a critical function altogether. Would really suck if you lost your low beams entirely... I only have seen 1 member on here that's had physical access to a tech2, and I don't think they've tried to use it for anything like this.

I'd definitely opt for making a controller of your own, and then splicing it in, maybe right behind the headlight header panel. Maybe make it modular, so if you ever had to go back to stock (or troubleshoot something), you can disconnect it quickly and easily.

 

[swede]

can someone with a tech2 reprogram the BCM to do all of the lighting mods? quad mod with fogs, DRL kill, etc?

Nope, I answerd a simular question on page one.

 

[diablo2184]

thanks