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I'm curious on what to do about adding fog lights to my 14 LT. I have already ordered the lights with bezel and also the OEM switch. I am debating now if I should 1) purchase the OEM wire harness (96950676) 2) Run them with the aftermarket harness included with lights or 3) Make my own wire harness? I have wires, looms, heat shrink, pins and light connectors should come in light kit.
1) With running the OEM wire harness will the fog lights be off always unless I push the button to turn them on? Once the OEM switch and harness is in do I need to run anything from the OEM switch to fuse panel? What I REALLY wish is that the headlights will be off and only have the fogs on for DRL.
2) I'm not to big on running the aftermarket switch cause I don't want to mount it anywhere in sight and look cheesy. Possibly splicing the Aftermarket switch to connect to fuse box?
3) If I made one it would basically just be connecting the lights and running P+ to fuse box and G- to chassis and install my OEM fog light switch?
I'm only asking because the cheapest OEM harness is $62 and I'm just curious what function (besides OEM look/feel) it has to justify the cost. If the wiring from the switch to fuse panel is already there it should be super easy to make my own from fuse box to the lights, right?
 

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2014 LT program car, Pull Me Over Red
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I'm curious on what to do about adding fog lights to my 14 LT. I have already ordered the lights with bezel and also the OEM switch. I am debating now if I should 1) purchase the OEM wire harness (96950676) 2) Run them with the aftermarket harness included with lights or 3) Make my own wire harness? I have wires, looms, heat shrink, pins and light connectors should come in light kit.
1) With running the OEM wire harness will the fog lights be off always unless I push the button to turn them on? Once the OEM switch and harness is in do I need to run anything from the OEM switch to fuse panel? What I REALLY wish is that the headlights will be off and only have the fogs on for DRL.
2) I'm not to big on running the aftermarket switch cause I don't want to mount it anywhere in sight and look cheesy. Possibly splicing the Aftermarket switch to connect to fuse box?
3) If I made one it would basically just be connecting the lights and running P+ to fuse box and G- to chassis and install my OEM fog light switch?
I'm only asking because the cheapest OEM harness is $62 and I'm just curious what function (besides OEM look/feel) it has to justify the cost. If the wiring from the switch to fuse panel is already there it should be super easy to make my own from fuse box to the lights, right?
I do not have an answer, but I am contemplating something similar. I purchased a split or dual OEM fog switch and aftermarket fog panels with LED DRLs built in. I have yet to purchase a harness or actual fogs yet.

I have to rebuild my front end and would like to figure this out sooner than later. From all that I have read as far as using the "automatic" DRL function is not possible. As I understand it, the voltage for the normal headlight is modulated to simulate a lower output to the headlight. Unless you can figure out a way for a relay to recognize this output difference, I do not think you can use your fogs as a DRL. I am probably going to have to just light up mine in additon to the modulated headlight.
 

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From all that I have read as far as using the "automatic" DRL function is not possible. As I understand it, the voltage for the normal headlight is modulated to simulate a lower output to the headlight.
Correct.

Unless you can figure out a way for a relay to recognize this output difference, I do not think you can use your fogs as a DRL.
Simple. Look at the parking light circuit. If the parking lights are on, then you may be in headlight mode. If they're off, you may be in DRL mode. I say "may" because they are times it might be in neither mode. (Like 'off').

So, one way to tackle it is to route the headlight wire to the headlights if the parking lights are on, and re-route the headlight signal to the DRL if the parking lights are off.
 

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2014 LT program car, Pull Me Over Red
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Correct.


Simple. Look at the parking light circuit. If the parking lights are on, then you may be in headlight mode. If they're off, you may be in DRL mode. I say "may" because they are times it might be in neither mode. (Like 'off').

So, one way to tackle it is to route the headlight wire to the headlights if the parking lights are on, and re-route the headlight signal to the DRL if the parking lights are off.
I do not have my DRLs in hand yet, but I think they use 12v to operate. The PWM signal is less than 12v. How will that work with the rerouted signal?

This is the wiring diagram for the unit in the photo.
Text Line Diagram Font Technology

Electronics Wire Cable Technology Electronic device

Automotive lighting Auto part Headlamp Light Automotive exterior
 

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I do not have my DRLs in hand yet, but I think they use 12v to operate. The PWM signal is less than 12v. How will that work with the rerouted signal?

This is the wiring diagram for the unit in the photo.
View attachment 224530
There's a couple of different ways to do that depending on what you want. The simplest is to wire the DRL as pictured, just use the parking light instead of the headlight for the dimming function. The hard part is finding a "ACC" signal to power the DRL. Perhaps pick it off the ignition relay so it's on anytime the engine is running. I'll have to see if there's a fuse that's powered that way so we can just use a fuse tap.

As for the existing DRL, we'll do a "DRL delete". Use a relay powered by the parking lights to open the headlight circuit to the bulbs unless the parking light is also on. Just remember to use a snubber diode across the relay coil so you don't zap the BCM.

An alternative is to use the headlight circuit to power the DRL - just use a high frequency diode and a capacitor to smooth the PWM signal. That will bump the voltage back up to full 12V. The DRL draw is low enough that I don't think current will be an issue for the BCM. The advantage of this is not needing to run an extra wire and the DRLs go out when you you're in Park. (Just like factory). The downside is that you'll need a couple of extra parts and a box to put it all in.
 

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There's a couple of different ways to do that depending on what you want. The simplest is to wire the DRL as pictured, just use the parking light instead of the headlight for the dimming function. The hard part is finding a "ACC" signal to power the DRL. Perhaps pick it off the ignition relay so it's on anytime the engine is running. I'll have to see if there's a fuse that's powered that way so we can just use a fuse tap.

As for the existing DRL, we'll do a "DRL delete". Use a relay powered by the parking lights to open the headlight circuit to the bulbs unless the parking light is also on. Just remember to use a snubber diode across the relay coil so you don't zap the BCM.

An alternative is to use the headlight circuit to power the DRL - just use a high frequency diode and a capacitor to smooth the PWM signal. That will bump the voltage back up to full 12V. The DRL draw is low enough that I don't think current will be an issue for the BCM. The advantage of this is not needing to run an extra wire and the DRLs go out when you you're in Park. (Just like factory). The downside is that you'll need a couple of extra parts and a box to put it all in.
Here is the wiring diagram for the exterior lights. Do you think you might be able to sketch something?

Text Drawing Technical drawing Plan Diagram

Text Diagram Technical drawing Plan Design

Edit: I tried to add this as an attachment as I have it in word with the picture, but still cannot figure out how to do this.

Found this by accident. It is for a 2011, but may work in other years as well.

Foglight pigtail
 

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Here is the wiring diagram for the exterior lights. Do you think you might be able to sketch something?

View attachment 224554

View attachment 224562

Edit: I tried to add this as an attachment as I have it in word with the picture, but still cannot figure out how to do this.

Found this by accident. It is for a 2011, but may work in other years as well.

Foglight pigtail
Do you know if this circuit applies to a 2017 Cruze? I am having issues with GM not wanting to reprogram my ECM because my car is a branded title. I figured I can just short the BCM and tell the relay to turn on when the factory switch is closed.
 

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I would not short anything to/from the BCM. You are asking for trouble. i do not know if any of this thread applies to the Gen II's. Spend time looking at the different functions and what happens when you switch items on and off. If you can get amp readings without inturupting the circuits would be best. See if there are different amp outputs for the different functions.

To get a wiring diagram, go to your local library and go the the reference desk. Ask them to show you how to access their online automotive repair manuals. Find the year/make/model diagrams and download or print. Easy and free

otherwise pay for a subscription to alldata or another service.

Contact different aftermarket fog manufactures and request there wiring diagrams for their product so you can review it. Most will send one.

Hope that helps
 
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