Foglights On With High Beams

No Tyme · January 11, 2016

I have read that the wires may be a different color but the position in the plug are the same. Best is to pop the plug and that will allow you a bit more flexibility to slide the diode in. Took me 3 times and 2 diodes but I did it...

2015sierrablack · January 11, 2016

Thanks for the response I've popped the plug out and tried it both ways been through a couple diodes now anybody know any info on the color wires being different?

polarys425 · January 12, 2016

Thanks for the response I've popped the plug out and tried it both ways been through a couple diodes now anybody know any info on the color wires being different?

On page 25 I posted an easy way to install this mod, and how to turn this mod on and off at will.

Tong Lu · January 15, 2016

2014 SIERRA SLT FOG LIGHTS WITH HIGH BEAM HEADLIGHTS MODIFICATION

This mod will let you use the fog lights on low beam same as factory. On and off with the fog light button.

When the fog lights are turned on while on low beam, then the high beams are either flashed or turned on and then off, the fog lights remain on when going back to low beam.

When the high beams headlights are switched on, the fog lights come on also. You cannot shut the fog lights off with the high beams on. When going back to low beam, the fog lights go off if they were off prior to switching high beams on.

Find the BCM under the dash, just to the left side of the steering column, right behind and above the OBD2 connector. It's a black box about 7" square and an inch thick. It will have 7 connectors in the lower edge of various colors.

Pull the BROWN connector loose. There is a little tab you need to squeeze inward to release it.

Look at it closely, there are tiny numbers at the corners to give you pin location reference. Use my attached connector photo and the numbers on the connector, along with the colors of the wires to locate the proper wires.

Locate pin #10 with the Brown and White striped wire. This is the Fog light signal wire for the relay.

Locate pin #18 with the Brown and Violet striped wire. This is the High Beam signal wire for its relay.

Take a 1N4004 diode and push the wire lead of the diode in along side the wires with a pair of needle nose pliers. You need to push hard to get it to slide in about 1/4" so it will stay snug. Make sure the marked end of the diode (stripe) is toward the High Beam.

You can put a piece of electrical tape over the bare diode leads or you can slip a piece of heat shrink over the diode before you install it and shrink it after pushing it in. But there's really no need as these are switched Ground leads, not power.

Put the BROWN connector back in the BCM.

YOU'RE DONE. THAT'S IT.

The BCM is behind this area

This is the BCM.

In this picture, my arrows point to the rows to intersect the proper wires.

The diagram below shows the connector oriented as you see it in the photo above so you can locate the correct pins.

Rectifier Diodes are available at any electronics store or Radio Shack.

http://www.radioshack.com/product/index.jsp?productId=2036270&znt_campaign=Category_CMS&znt_source=CAT&znt_medium=RSCOM&znt_content=CT2032230

Which one is for the lowbeam relay, I don't see it on the chart. I did the mod for my 2008, the relays were just in the engine bay and super easy to get to.

chinookmtp · January 16, 2016

^{Tried and Tried. Diode will not seat in fog light side. will go in High beam side all day long. Have broken all four diodes I had. I even trimmed the end. Tried with and without pliers. Tried with brown plug installed and removed. Mines a 2015 Sierra SLT. Guess this just isn't go to happen. I'm afraid if I mess with this connector anymore I'll screw up some of other connections. This sux, because with Hi beams on(which aren't that great anyway, even after new german bulbs and reprogramming of voltage at dealer) you loose all the extra light close in that the fogs provide. What a crappy set up for a 50K+ truck..}

Edited January 16, 2016 by chinookmtp

wrc7732 · January 17, 2016

^{Tried and Tried. Diode will not seat in fog light side. will go in High beam side all day long. Have broken all four diodes I had. I even trimmed the end. Tried with and without pliers. Tried with brown plug installed and removed. Mines a 2015 Sierra SLT. Guess this just isn't go to happen. I'm afraid if I mess with this connector anymore I'll screw up some of other connections. This sux, because with Hi beams on(which aren't that great anyway, even after new german bulbs and reprogramming of voltage at dealer) you loose all the extra light close in that the fogs provide. What a crappy set up for a 50K+ truck..}

Man I hear ya. It's just nuts. I too have had the TSB performed (much better, but not good enough). I'm even toying with the idea of trading in my '15 Sierra for a '16. Just crested 10k miles. I can't believe these lights passed modern safety standards. My '77 corvette had better headlights that the halogen projector setup in these trucks.

And I know there are ways to improve it (HID conversions, etc), but why should I have to do that these days. Fix these headlights GM. Grrrr!!

Sent from my iPhone using Tapatalk

BuyAmericanIron · January 17, 2016

Tong Lu, I did some research and was unable to find the low beam relay. Ended up doing the 10/22 mod which ties fog lights into the parking lamp circuit. On the 2016, if you turn on fog lights, it disables Intellibeam which is a very nice feature. Only possible issue is that you have fogs on at all lighting positions, Auto, Parking lights, All lights (low and high beam). Can't remember the last time I used parking lights only, so don't see it as being an issue.

For you guys having difficulty inserting the diode into the plug, try using a large sewing pin and sliding it at an angle into the corner of the connector at the selected wire position. This will push it to the opposite side and make room for the diode. Also, try cutting the end of the diode wire at a sharp angle with a pair of clippers. This will make a sharp point and help with installation into the back of the plug. Remember, you are trying to slide the diode along side the existing wire. Pushing it into a corner is your best bet. It should insert about half an inch when you find the right spot.

Tong Lu · January 17, 2016

Tong Lu, I did some research and was unable to find the low beam relay. Ended up doing the 10/22 mod which ties fog lights into the parking lamp circuit. On the 2016, if you turn on fog lights, it disables Intellibeam which is a very nice feature. Only possible issue is that you have fogs on at all lighting positions, Auto, Parking lights, All lights (low and high beam). Can't remember the last time I used parking lights only, so don't see it as being an issue.

For you guys having difficulty inserting the diode into the plug, try using a large sewing pin and sliding it at an angle into the corner of the connector at the selected wire position. This will push it to the opposite side and make room for the diode. Also, try cutting the end of the diode wire at a sharp angle with a pair of clippers. This will make a sharp point and help with installation into the back of the plug. Remember, you are trying to slide the diode along side the existing wire. Pushing it into a corner is your best bet. It should insert about half an inch when you find the right spot.

Thank you, that's what I was leaning towards.

Spurshot · January 20, 2016

Just my opinion, but I didn't think the stock fog lights on my 2014 added any noticeable visibility when I did this mod. However, when I installed auxiliary driving lights, I wired a powerful wide beam set to the fog light circuit via a relay. The diode 10-18 mod then allowed me to turn on the auxiliary driving lights with the factory fog light switch and allow them to remain on when high beams were commanded. Later, I replaced the OEM fog lights with Rigid Industries DOT fog lights.

So, my current light setup is HID kit in OEM projectors, Rigid fogs, 2 Baja Designs S2 wide beams relay wired to the fog circuit, 2 Baja Designs S2 long range beams relay wired to the high beams. When I command high beams, all the lights come on. When I return the OEM hi-low headlight switch to low beam, they all shut off and the headlights return to low beam. I can also turn on fogs and the wide beam S2 lights separately by pushing the factory fog light button, day or night.

Edited January 20, 2016 by spurshot

Shredzy · January 21, 2016

FYI the programming to do this through the BCM the OEM way is now a reality ;)

GTPprix, tried to send you a message, says you can't receive any new messages??

Can you tell more of the programming? Send me a message?

BuyAmericanIron · January 28, 2016

I spoke to Anthony at MVI. He said the BCM can be re-programmed, but it is difficult, expensive and requires dealer involvement which can bring it's own set of problems. He said if you are close to him and bring it to his shop it is not a problem. In the end, he strongly recommends against trying to re-program the BCM. Just go with one of the diode mods in this forum and consider it done. I did the 10/22 and it works just fine for my application.

syd2315 · February 4, 2016

2014 SIERRA SLT FOG LIGHTS WITH HIGH BEAM HEADLIGHTS MODIFICATION

This mod will let you use the fog lights on low beam same as factory. On and off with the fog light button.

When the fog lights are turned on while on low beam, then the high beams are either flashed or turned on and then off, the fog lights remain on when going back to low beam.

When the high beams headlights are switched on, the fog lights come on also. You cannot shut the fog lights off with the high beams on. When going back to low beam, the fog lights go off if they were off prior to switching high beams on.

Find the BCM under the dash, just to the left side of the steering column, right behind and above the OBD2 connector. It's a black box about 7" square and an inch thick. It will have 7 connectors in the lower edge of various colors.

Pull the BROWN connector loose. There is a little tab you need to squeeze inward to release it.

Look at it closely, there are tiny numbers at the corners to give you pin location reference. Use my attached connector photo and the numbers on the connector, along with the colors of the wires to locate the proper wires.

Locate pin #10 with the Brown and White striped wire. This is the Fog light signal wire for the relay.

Locate pin #18 with the Brown and Violet striped wire. This is the High Beam signal wire for its relay.

Take a 1N4004 diode and push the wire lead of the diode in along side the wires with a pair of needle nose pliers. You need to push hard to get it to slide in about 1/4" so it will stay snug. Make sure the marked end of the diode (stripe) is toward the High Beam.

You can put a piece of electrical tape over the bare diode leads or you can slip a piece of heat shrink over the diode before you install it and shrink it after pushing it in. But there's really no need as these are switched Ground leads, not power.

Put the BROWN connector back in the BCM.

YOU'RE DONE. THAT'S IT.

The BCM is behind this area

This is the BCM.

In this picture, my arrows point to the rows to intersect the proper wires.

The diagram below shows the connector oriented as you see it in the photo above so you can locate the correct pins.

Rectifier Diodes are available at any electronics store or Radio Shack.

http://www.radioshack.com/product/index.jsp?productId=2036270&znt_campaign=Category_CMS&znt_source=CAT&znt_medium=RSCOM&znt_content=CT2032230

Does this apply to 2015 models too or is it just for the 2014?

Paulybee · February 7, 2016

I just cut The power to my foglights then jumped them off my low beams. So now when I turn my head lights on. My fog lights go on. I used my fog light button to turn on a light bar. This is Good to know though. My light bar turns off when I put The high beams on. But it doesnt matter since it's so bright and my low Beam and fog lights are led I'll probably try this though.

jared2015gmc · March 10, 2016

I ordered some of Amazon and installed tonight works great...I cut the tips on a sharp angle and they slipped in easy...

WLC · March 10, 2016

Done the fog mod with the bright on.Helped but not enough.Replaced fogs with LEDs.Helped but not enought.Added a license plate mount from ACI with LEDs. Helped some more. Wired these straight to the battery with a remote control switch.Programmed one of the garage door openers to the remote also in case the battery goes dead in the remote.Installed LEDs in the headlights.Starnill from Amazon. Installed 5202 headlight bulbs in the fogs. Too bright for oncoming traffic with everything on but great on the back roads.This set up hurts in fog driving but makes deer stop in their tracks. Reflects off of snow also. Really cuts darkness. The upgrade with the volsa bulbs was no better than the 9011's I installed.9011's are pretty good also. Spent money and time but I can see pretty well now. Wife's Durango was great from factory.