How To: Auto Fog Lights (Don't Have To Push Button)

midwestdenaliguy · August 10, 2018

5 hours ago, cs2016lt said:

Thanks, that would greatly help! no guessing..

Found the spare, it's a NTE5812 Diode (6A, 100V). Looks like Amazon only sells them in a 5 pack.

https://www.amazon.com/ELECTRONICS-NTE5812-STANDARD-DIODE-pieces/dp/B011N9OCV4/ref=sr_1_cc_2?s=aps&ie=UTF8&qid=1533862118&sr=1-2-catcorr&keywords=nte5812

Roscopcoletrain · August 10, 2018

Geez, Amazon Canada doesn't even sell them and .com won't ship lol.

The reg diodes used under the dash that we've been using won't work?

phabejhmoob · August 10, 2018

2 hours ago, midwestdenaliguy said:

Found the spare, it's a NTE5812 Diode (6A, 100V). Looks like Amazon only sells them in a 5 pack.

https://www.amazon.com/ELECTRONICS-NTE5812-STANDARD-DIODE-pieces/dp/B011N9OCV4/ref=sr_1_cc_2?s=aps&ie=UTF8&qid=1533862118&sr=1-2-catcorr&keywords=nte5812

Awesome. Added to list to buy

jimlem · August 10, 2018

10 hours ago, Pearl2017 said:

Props for the great idea/contribution!

I have not looked at the schematic so don't know, but do the fogs normally power from a relay? Concern for me would be if you are now powering the fogs piggybacked on another circuit. If there is a relay that jumper could/should be going to the energizing coil of the fogs relay. This way it is pulling power on its intended fused circuit and not doubled up on another.

On those fuse taps... Make sure you orient the tap correctly so that the LOAD is connected AFTER the fuse and not before. One leg of a fuse is BATTERY and the other leg goes to the LOAD. If you orient it incorrectly you could continue to pull power even if the fuse blows. You can find the BATTERY leg by pulling the fuse and using a voltmeter to find which pin is +12v and make sure the tap is on the other pin.

Would this apply the same to both ends of the jumper wire, or is the concern only for the end attached to the DRLs?

midwestdenaliguy · August 10, 2018

10 hours ago, jimlem said:

Would this apply the same to both ends of the jumper wire, or is the concern only for the end attached to the DRLs?

The diode is allowing current to flow from the DRL's/Parking Lamp to the Fog Light, and as diode's are designed, it doesn't allow current to flow back to the DRL from the Fogs. The question/point they are bringing up is that my wire does a direct jump and bypasses the fuses, so the fear is that current coming from the DRL's/Parking Lamps could overload the Fogs and/or put too much draw on the DRL's - causing an electrical failure or burn up. My wire is next to the fuses and doesn't go through the fuse itself, that's why I mentioned in one of my replies that I am adding the fuse taps this weekend and will update my original post. By using the fuse taps, it guarantees the current is flowing through the fuses and not bypassing them. As I also mentioned, I never had an issue with this mod for 4 years in another vehicle BUT adding the fuse taps is cheap insurance that nothing will happen to your fog lights and/or truck.

Edited August 10, 2018 by midwestdenaliguy

midwestdenaliguy · August 10, 2018

15 hours ago, Roscopcoletrain said:

Geez, Amazon Canada doesn't even sell them and .com won't ship lol.

The reg diodes used under the dash that we've been using won't work?

Any 6a, 100v diode will work. It doesn't have to be the exact brand I used. I'd just do a general search online for a 6a 100v diode (you may also see it called a rectifier or rectifier diode - they all serve the same purpose and will work) or call a local electronics shop near you in Canada.

phabejhmoob · August 10, 2018

Ebay?? here's a seller from Canada

https://www.ebay.com/itm/FR602-Fast-Recovery-Rectifier-100V-6A-NOS-Qty-5/142900472067?hash=item2145882903%3Ag%3A2DoAAOSwqfNXjjCT&_sacat=0&_nkw=6a%2C+100v+diode&_from=R40&rt=nc&_trksid=m570.l1313

Edited August 10, 2018 by cs2016lt

phabejhmoob · August 10, 2018

4 hours ago, midwestdenaliguy said:

The diode is allowing current to flow from the DRL's/Parking Lamp to the Fog Light, and as diode's are designed, it doesn't allow current to flow back to the DRL from the Fogs. The question/point they are bringing up is that my wire does a direct jump and bypasses the fuses, so the fear is that current coming from the DRL's/Parking Lamps could overload the Fogs and/or put too much draw on the DRL's - causing an electrical failure or burn up. My wire is next to the fuses and doesn't go through the fuse itself, that's why I mentioned in one of my replies that I am adding the fuse taps this weekend and will update my original post. By using the fuse taps, it guarantees the current is flowing through the fuses and not bypassing them. As I also mentioned, I never had an issue with this mod for 4 years in another vehicle BUT adding the fuse taps is cheap insurance that nothing will happen to your fog lights and/or truck.

I learned something new! lol

midwestdenaliguy · August 15, 2018

UPDATE - the fuse tap link in here is for a mini fuse and not a micro fuse, they are too big to use (just learned the hard way). Fortunately it was only an $8 lesson. Here are the correct fuse taps (micro):

Wirenest Micro2 ATR Fuse Tap 16awg with 15A Fuse - 5 Pack https://www.amazon.com/dp/B06XKWWS7B/ref=cm_sw_r_cp_apa_03eDBbJ6KZ2V2

I'll install them this weekend and update this thread.

djw88 · August 15, 2018

technically it is illegal to have fog lights on with high beams. I don't think you would ever get in trouble though.

phabejhmoob · August 15, 2018

1 hour ago, djw88 said:

technically it is illegal to have fog lights on with high beams. I don't think you would ever get in trouble though.

so whose going to driving around town with High beams on anyways and if people did, those idiots don't get tickets for that. I see plenty who doesn't give a hoot Seriously.. LOL even if fogs were on with high beams that reserved for rural and country driving (off road). The same as if you were to use your flood lights, there ain't nothing illegal about that.

djw88 · August 15, 2018

2 minutes ago, cs2016lt said:

so whose going to driving around town with High beams on anyways and if people did, those idiots don't get tickets for that. I see plenty who doesn't give a hoot Seriously.. LOL even if fogs were on with high beams that reserved for rural and country driving (off road). The same as if you were to use your flood lights, there ain't nothing illegal about that.

That's what I'm saying. lol probably not going to be an issue but it is technically illegal.

midwestdenaliguy · August 15, 2018

16 minutes ago, djw88 said:

That's what I'm saying. lol probably not going to be an issue but it is technically illegal.

Was waiting for someone to chime in with this :-) I know you're simply pointing it out, but that is a law I'll never understand. Getting a ticket for driving with brights on or HIDs in the wrong housing makes sense because you're blinding people, but fogs that are aimed at the ground in front of you? How is that dangerous?

jlozan2 · August 15, 2018

On 8/9/2018 at 4:14 PM, midwestdenaliguy said:

Yeah, those fuse taps would be cheap peace of mind. Just ordered a set that'll arrive Saturday. I'm going to install those and update my original post. Even though I didn't have an issue before, I'd feel terrible if someone followed this and it led to a major problem.

looking forward to see the update. Just ordered them myself.

jlozan2 · August 15, 2018

On 8/9/2018 at 8:45 AM, midwestdenaliguy said:

I posted this in another thread, but they were looking to only have the fogs on with high beams. My solution has the fog lights automatically turn on, and stay on, anytime the parking lights or headlights come on (hi and lo beam). You never have to hit the button. Figured I'd label this as a "How To" in case those are housed somewhere. I'm new to this forum, so let me know if I should be doing this differently. Cheers!

Hey guys - recently bought a 2016 Sierra Denali and joined the forum. Stumbled upon this thread while clicking around. I always gain so much from these forums, so I thought I'd give back in my first post. Here is a simple solution I made to have the fog lights automatically turn on with the day time running lights - did this with my previous truck as well (2008 Cadillac Escalade). I bought a diode and used some 14 gauge wire I had laying around. I wrapped 14 gauge wire to each end of the diode and sealed it with marine grade shrink wrap (waterproof). I then got into the engine bay fuse box and pulled the fuses for the fog lights (#49) and day time running lights (#28 or #29 - can be either, only need one). When I put the fuses back in I wedged the wire in one of the slots for the fuse connector, one end of the diode/wire goes in the fog light fuse and the other goes in the DRL fuse. Keep in mind the diode is directional (only allows current one way), so if it doesn't work at first just flip the wire around. Now anytime your DRL's are on, the fog lights will automatically come on. No need to push the fog light button. The fog lights also stay on when you turn on your brights. I attached a photo of my set up, it was taken standing over the driver side fender looking at the fuse box. Ask any questions if you got em!

Is it necessary to use 14-gauge wire?