Foglights On With High Beams

arcasey · March 7, 2017

17 sierra Denali

I actually thought about this after I asked and I don't think it matters. I think all of these trucks supply a lower voltage for the DRL's so the only safe way to ensure you get the correct voltage to the fog lights would be to tap into the DRL circuit using a relay and then supply 12V from the battery and tap into the fog light circuit. The only problem is that you would not be able to turn your fog lights off while the DRL's are on.

fondupot · March 22, 2017

In case anyone is interested. I was able to do this exact same mod on my 2017 Colorado. I followed the same process as @Spurshot to find the pins and what not. ANd then just used a diode, just like the one he used, to jump between the fogs relay and the high beam relay. The result is the same. Fogs on with High Beams!

The only difference being that the pin numbers on the brown connector in the Colorado are slightly different. Otherwise it's shot for shot.

Link to the thread I made on coloradofans.com/forums

http://coloradofans.com/forums/201-2nd-gen-electronics-audio-lighting/338097-fogs-w-high-beams-mod.html

Thanks for the inspiration @Spurshot

kpkacts238 · April 7, 2017

So, this may have already been addressed, if it has I am sorry...

I would like my fog lights to come on automatically when I start my truck up, stay on when I turn on my hi-beams, and only go off if I click the button in the cab. Essentially, they would stay on all the time unless I manually turn them off... I understand this may be illegal in some states.

Is there a way to do this?

2014 GMC Sierra 1500 SLT All-Terrain

polarys425 · April 8, 2017

So, this may have already been addressed, if it has I am sorry...

I would like my fog lights to come on automatically when I start my truck up, stay on when I turn on my hi-beams, and only go off if I click the button in the cab. Essentially, they would stay on all the time unless I manually turn them off... I understand this may be illegal in some states.

Is there a way to do this?

2014 GMC Sierra 1500 SLT All-Terrain

Not by the dash switch as all it does is command the BCM to turn it on and off. The diode overrides this. If you look on page 25, post #372, I posted an easy way to make this mod with an override switch so that one could enable/disable this mod easily.

pgamboa · April 14, 2017

Newbe here and I'm looking to do the 10-18 jump for the fogs and the 26-26 for the reverse lights. I've seen the pictures of both but for the fogs I'm confused. I thought the stripe on a diode was to go toward the flow of current - which would be the fog light (10) wire. Let me know. Thanks.

So this has been bugging me for a while and finally took the time to figure out. This was also confusing me as I really didn't know what diodes were until joining this forum. I, like many here, just followed suit and did what everyone else did. Install a diode. LOL.

You are correct in that current would flow towards the stripe. This is true positive (+) voltage. The reason the diode is reversed, is because the two circuits that are being "jumped" is a switched negative (-) ground circuit for the relay.

Hope this helps. I took this opportunity to teach my 10 & 12 year old boys about diodes and resistors.

Edited April 14, 2017 by pgamboa

paauto · April 14, 2017

So this has been bugging me for a while and finally took the time to figure out. This was also confusing me as I really didn't know what diodes were until joining this forum. I, like many here, just followed suit and did what everyone else did. Install a diode. LOL.

You are correct in that current would flow towards the stripe. This is true positive (+) voltage. The reason the diode is reversed, is because the two circuits that are being "jumped" is a switched negative (-) ground circuit for the relay.

Hope this helps. I took this opportunity to teach my 10 & 12 year old boys about diodes and resistors.

Thanks. I had concluded that it must be a switched ground circuit. Always good learn something new.

paauto · April 14, 2017

I have not, thanks for sharing. However I would still like to have on/off functionality of my light bar with the high beams on. It seemed practical to utilize the fog light button since it is more or less unused when the high beams are on.

Check out the following:

http://presair.com/shop/tinytrol-miniature-air-switch/

http://presair.com/shop/b350ba-10-soft-foot-pedal/

I installed the foot switch under the carpet between the brake pedal and parking brake to remotely activate the switch. Check out my post with pictures showing the install.

Sierra706 · April 14, 2017

So this has been bugging me for a while and finally took the time to figure out. This was also confusing me as I really didn't know what diodes were until joining this forum. I, like many here, just followed suit and did what everyone else did. Install a diode. LOL.

You are correct in that current would flow towards the stripe. This is true positive (+) voltage. The reason the diode is reversed, is because the two circuits that are being "jumped" is a switched negative (-) ground circuit for the relay.

Hope this helps. I took this opportunity to teach my 10 & 12 year old boys about diodes and resistors.

My father tried to do the same when I was young. Pretty certain while he was talking I was imagining what I wanted for Christmas

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6.2Midnight · April 14, 2017

^^^ now that's funny, but for most of us, probably true!

pgamboa · April 14, 2017

My father tried to do the same when I was young. Pretty certain while he was talking I was imagining what I wanted for Christmas

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Not to go off topic, but when my boys asked for a Raspberry PI to build a Pigrrl 2, it got me excited.

We setup a soldering station, learned about 3D printing and files needed for that..etc. it was a proud moment for sure!

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ABlackChevy · April 16, 2017

Ive been looking through this thread trying to find a way to run diodes in my 2017 silverado. The fuse block is different than in the previous years. I want my fogs to stay on with my highs and stay on at all times until I manually turn them off. I got some rectifier diodes today, went to put them in and it was a different block! I prefer to not run them with my daylight running lights, though. It is doubtful that I am going to go through great lengths to mod this. If it is as easy as the previous years Id like to know how. I apologize if I missed how to do this somewhere. Thanks fellas.

pgamboa · April 17, 2017

Ive been looking through this thread trying to find a way to run diodes in my 2017 silverado. The fuse block is different than in the previous years. I want my fogs to stay on with my highs and stay on at all times until I manually turn them off. I got some rectifier diodes today, went to put them in and it was a different block! I prefer to not run them with my daylight running lights, though. It is doubtful that I am going to go through great lengths to mod this. If it is as easy as the previous years Id like to know how. I apologize if I missed how to do this somewhere. Thanks fellas.

This mod is done at the BCM. Several 2017 owners have come this successfully. I've personally looked at the BCM diagrams and they are the same as 2016.

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paauto · April 17, 2017

This mod is done at the BCM. Several 2017 owners have come this successfully. I've personally looked at the BCM diagrams and they are the same as 2016.

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I have a '17 and can confirm it is the same.

NaClCrocodile · April 26, 2017

Just did it in my '14 Sierra All Terrain. Now I've got the distance with Morimoto D2S 4.0 retrofit projectors and my sides with Rigid fogs. Safe to say, nightfall can't get here soon enough!

If anyone needs some diodes, I've got eight left. All I ask is that you pass the extras along when you're done.

Crstfr · May 9, 2017

Not to go off topic, but when my boys asked for a Raspberry PI to build a Pigrrl 2, it got me excited.

We setup a soldering station, learned about 3D printing and files needed for that..etc. it was a proud moment for sure!

Sent from my iPhone using Tapatalk

i got a pi for my boy too!.. .went on line and dropped an emulator on it... got over 3k old school games... atari, sega, nintendo... etc.. even games that only came out in china.!... .. can run 4 usb xbox controllers from it..!... i guess its more for me.. them 8bit games he's just not down with.. i mean.. between his ipads, phone, computer, xbox 360, ps3, both wii's... .. lol.. kids these days!..