2016 Suburban LT Fog Lamps install with OEM switch

[Javaso]

Hooked mine up as described, and they work. The key being making sure you are using the correctly colored wire in the correct location. The only hiccup I currently have is that sometimes when you remote start the car, or simply unlock it, i.e. anything the makes the parking lamps flash... then theres a chance the fogs will come on. And in my case, Rigid SR-Q2's with a crazy bright spot beam. As a result, I may change the 611T to a positive output, and setup the relay for positive connection vs negative. Unless someone else has a quick fix.

I connected the fog lights wire to the brown cable of the harness coming out of the fuse box and the fog lights and running lights are on, even with disconecting the switch. Any ideas?

 

[Javaso]

Best suggestion I have is to pull out a multimeter and see where the break in the chain is. Start at the switch, verify that the you see ground there when you press it (or lose voltage). Then move on to the 611T and verify that it's turning on, then go under the hood, if you put a relay there, make sure it's getting the signal from the 611T. You should be able to trace the problem somewhere in all that.

Verified the oem switch with voltmeter and not throwing any pulse. It doesn't fluctuate.

 

[OxF16]

so similar to my situation, yet different... hmmm. check voltage pulse out of 611T?

 

[nilleo]

I think I misunderstood your original problem. Is your problem that the switch doesn't trigger the 611T or that the lights are always on?

 

[nilleo]

Hooked mine up as described, and they work. The key being making sure you are using the correctly colored wire in the correct location. The only hiccup I currently have is that sometimes when you remote start the car, or simply unlock it, i.e. anything the makes the parking lamps flash... then theres a chance the fogs will come on. And in my case, Rigid SR-Q2's with a crazy bright spot beam. As a result, I may change the 611T to a positive output, and setup the relay for positive connection vs negative. Unless someone else has a quick fix.

Did all the wiring and when we conected the fog lights wire to the brown, coming out of the fuse box under the hood, the running lights and fog lights turns on, even disconnecting the switch. Have verified all connections and don't know what is causing this. Need help.

I connected the fog lights wire to the brown cable of the harness coming out of the fuse box and the fog lights and running lights are on, even with disconecting the switch. Any ideas?

It sounds like you both have the same issue, and I suspect the root is catching the wrong brown wire coming out of the fuse box. Make sure that when you test that brown wire with your multimeter, it does NOT change 12V-0V or vice versa when you turn any of the lights on (parking, headlamp, etc.).

Also, take note of what color wire you're looking for! In my original post I mention that the wire you're looking for could be Brown or Brown/White depending on what you have at the BCM in X5, pin 10. If you have a Brown wire there, you're looking for a Brown wire under the hood, if you have a Brown/White wire there, you're looking for a Brown/White.

From here your plan of attack should be to confirm you have the same wire under the hood as you do at the BCM... an easy way to check would be to confirm the BCM side since you can visibly see the pin (see my original picture below). Unfortunately you can't test this wire very well since your truck isn't equipped with fog lights, so the BCM will never do anything with this wire other than supply a pull-up voltage, but you can count the pin location!

Once you confirmed that wire, turn ignition on and supply ground to that wire with the 611T or with some other source. Then go under the hood and test the wire you found under the hood and make sure it's testing the exact same way i.e. when you ground the inside wire, the outside wire should have 0V, otherwise it should have ~5-12V.

Lastly, make sure you're driving a relay with that underhood wire! I think I mentioned how to wire that relay in an earlier post, but in case I didn't it should look something like this...

85 - underhood brown or brown/white wire
86+87 - 12V constant source underhood mentioned in original post
30 - to fog lamp 12V+ input

 

[04ctd]

This needs to be a sticky.

can you PDF the schematics up as JPG's?

two questions:

Does the Intellibeam still work automatically (rumor is, it does not if the OEM fogs are on)
http://www.tahoeyukonforum.com/thre...low-beams-how-do-you-force-it-to-start.88867/

does the fog light indicator work on the dash? I would think not, since the BCM is not programmed for Fog lights.

request an update from anyone who bought the cheap eBay fog lights with plastic lenses, how are they holding up? scratched to death?

 

[nilleo]

This needs to be a sticky.

can you PDF the schematics up as JPG's?

Not sure what you mean by that, do you want a PDF or a JPG?

two questions:

Does the Intellibeam still work automatically (rumor is, it does not if the OEM fogs are on)
http://www.tahoeyukonforum.com/thre...low-beams-how-do-you-force-it-to-start.88867/

This is my parents' truck so I'm not sure it has Intellibeam, is it equipped on all trims? Regardless, the way I explain to wire everything ensures that the fog lamps work anytime the parking lights are on, so yes, they would still work with Intellibeam on/off since the fog lamps would be dependent on only the state of the parking lamps and the fog lamp request switch. If this is a feature on all trims, I'll verify that it all works as I'm claiming the next time I see the truck.

does the fog light indicator work on the dash? I would think not, since the BCM is not programmed for Fog lights.

That's correct, it does not work since the BCM is not programmed for fog lamps. As I mentioned in an earlier post, there's likely a CAN string that will request the indicator to come on in the cluster, even if it's just a message that's used for diagnosing the cluster modes, but that would take anywhere from a few hours to days to find--and I'm a full time student with access to the truck only on holiday--let's be real, if I'm on holiday away from school, I'm going to be doing nothing ha!

request an update from anyone who bought the cheap eBay fog lights with plastic lenses, how are they holding up? scratched to death?

I might visit the parents over the weekend, if I do, I'll try and snap some pictures of how they're holding up. I'm certain they've put well over 10k miles on them already on LONG road trips.

 

[04ctd]

do you want a PDF or a JPG?

assume you can't attach a PDF in the forums, and would have to make it a JPG to have it show up, but IDK.

good work, this a GOOD thread, ought to be a Sticky @NathanJax

 

[nilleo]

Are you asking for the original GM schematics? You can find them free, officially, at https://www.gmupfitter.com/pages/body-builder-manuals

 

[04ctd]

Thanks, I downloaded the schematics and looked them over, here are some notes, be advised, all this refers to a 2016 vehicle/schematic:

Front Fog Lamps (RPO T3U) and Rear Fog Lamps (RPO T79)
most info is shown on page 41, it is comprised of three circuits:
Circuit 192 - from Headlamp switch to BCM
Circuit 1317 - is from the BCM to control Fog Relay KR46
Circuit 2234 - +12v output to Fog Light bulbs.


RPO Description
T3U LAMP FRT FOG-FRT FOG
T79 LAMP-FOG, RR (T79 is the ReaR fog lamps, which are only European? canadian?)

here are the page numbers to find the connector picture/description/schematic:

X50A Fuse Block - Underhood X1 page 430
Pin Size Color Circuit Function Terminal Type ID Option
J3 0.5 BN/VT 2234 Front Fog Lamp Supply Voltage III T3U

X50A Fuse Block - Underhood X3 page 434
Pin Size Color Circuit Function Terminal Type ID Option
L5 0.5 BN/WH 1317 Fog Lamp Relay Control I T3U

K9 Body Control Module X1 page 727
Pin Size Color Circuit Function Terminal Type ID Option
4 0.5 RD/BN 2240 Battery Positive Voltage
15 0.35 D-BU/GY 192 Front Fog Lamp Switch Signal T3U
22 0.35 L-GN/GY 13 Headlamp Switch Park Lamp Signal

K9 Body Control Module X5 page 735
Pin Size Color Circuit Function Terminal Type ID Option
10 0.5 BN/WH BN 1317 Fog Lamp Relay Control T3U

S30 Headlamp Switch page 1001
Pin Size Color Circuit Function Terminal Type ID Option
10 0.35 D-BU/GY 192 Front Fog Lamp Switch Signal I T3U

X100 Forward Lamp Harness to Front Bumper Harness (X88 or Z88) page 1122
Pin Size Color Circuit Function Terminal Type ID Option
3 0.5 BN/VT 2234 Front Fog Lamp Supply T3U