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T1 Dome Light Tap Wires

Smoothbassman

By Smoothbassman
in Modifications, Wheels & Tires

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DNTBL8 Enthusiast

DNTBL8

Posted
Posted

Thanks!  does anyone know what gauge wire is the grey wire to the BCM?  I want to tap in with a Posi-Tap, they make them in 20-22 gauge, does that seem right or so it 18 awg? 

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Smoothbassman
Smoothbassman

This is easy. Get you a strip of LEDs and tap into the dome circuit. When you open the door lights on. If you pull too much current then the BCM will trip out so go light in the LEDs and you shoul

DNTBL8
DNTBL8

Smoothbassman, thanks so much for the help. i ended up doing 3 LEDs that were bolt style (not strip) directly off the BCM without a relay, no buzzing, no BCM freakout. Here's a post I made that shows

Smoothbassman
Smoothbassman

Just got thru installing my floor lighting. Looks great but now I need to tap into the dome light circuit to get them to turn on when I open the doors.   Does anyone have a clue on the 2019-2020 Silv

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DNTBL8 Enthusiast

DNTBL8

Posted
Posted
This is easy.

Get you a strip of LEDs and tap into the dome circuit. When you open the door lights on.

If you pull too much current then the BCM will trip out so go light in the LEDs and you should be OK.

Sent from my SM-N960U1 using Tapatalk



Smoothbassman, you seem to know your stuff when it comes to wiring. here’s what i drew up for a plan to have my footwell LED lights operate with the door open/close.

I haven’t wired much before (only AC switches, plugs). Is this diagram appropriate to operate lights with doors, and not have to worry about amp draw on the bcm wire?

d5b67f376216e31c21333cb248f01651.jpg


Sent from my iPhone using Tapatalk
  • 2 weeks later...
Smoothbassman Enthusiast

Smoothbassman

Posted
  • Author
Posted


Smoothbassman, you seem to know your stuff when it comes to wiring. here’s what i drew up for a plan to have my footwell LED lights operate with the door open/close.

I haven’t wired much before (only AC switches, plugs). Is this diagram appropriate to operate lights with doors, and not have to worry about amp draw on the bcm wire?

d5b67f376216e31c21333cb248f01651.jpg


Sent from my iPhone using Tapatalk
Your close

You will need to use constant 12v power since the accessory power isn't on until you turn the truck on.

Also you will need a filter on the relay input to have the relay fully lock up thru the dimming action for the dome light circuit.

dc65b86c95fd9b1474664d36ab805658.jpg

Sent from my SM-N960U1 using Tapatalk

  • Like 1
DNTBL8 Enthusiast

DNTBL8

Posted
Posted

Smoothbassman, thanks so much for the help. i ended up doing 3 LEDs that were bolt style (not strip) directly off the BCM without a relay, no buzzing, no BCM freakout. Here's a post I made that shows the install. I included links for these Badass Positap nuts i found that worked perfect for hooking into the BCM gray dome wire.  THANK YOU again so much for your assistance. 

 

  • Like 2
  • 5 months later...
bzimmer82 New Member

bzimmer82

Posted
Posted
On 2/20/2020 at 3:53 AM, Smoothbassman said:

Your close

You will need to use constant 12v power since the accessory power isn't on until you turn the truck on.

Also you will need a filter on the relay input to have the relay fully lock up thru the dimming action for the dome light circuit.

dc65b86c95fd9b1474664d36ab805658.jpg

Sent from my SM-N960U1 using Tapatalk
 

 

 

I have this all installed and I am getting the relay chatter.  What filter did you install?  Some other posts talk about installing a diode and a 1000uf cap.  Can you post a link to the filter you installed please?

Aaaaaaaayush Enthusiast

Aaaaaaaayush

Posted
Posted
On 7/30/2020 at 9:42 AM, bzimmer82 said:

 

 

I have this all installed and I am getting the relay chatter.  What filter did you install?  Some other posts talk about installing a diode and a 1000uf cap.  Can you post a link to the filter you installed please?

Did the diode and 1000uf capacitor work for the relay chatter?

JansterZ71 Enthusiast

JansterZ71

Posted
Posted

Question for you guys who have installed this in the manor @Smoothbassman explained.

 

When the lights are running off main power and on while driving, can the lights be dimmed from the Opt7 app?  

Can the lights color be changed on the app?

Can you turn off the lights from the app if you do not want them on?  Or are they always on.  

 

Thanks!

  • 1 month later...
Joe’s Sierra New Member

Joe’s Sierra

Posted
Posted

After doing some research and trying to figure which wire to tap into on my 19 Sierra to add footwell lighting this is what I came up with. These are not the same as my 18 silverado was at all. To get the added led lights I purchased to come on and fade in and out with the overhead lights I had to tap into the BCM connector #1 pin 23 which is a grey wire. The lights look awesome and you can see now. 

61EBB9FF-CD5D-43CE-BDCC-7C1CAFD3C2D9.jpeg

0FC62574-75AD-42DB-A857-F59CD79D7CBC.jpeg

F95CF18A-81A6-4B4B-828F-E572364EFE11.jpeg

  • 3 months later...
bstraty Enthusiast

bstraty

Posted
Posted
On 9/13/2020 at 9:02 PM, Joe’s Sierra said:

After doing some research and trying to figure which wire to tap into on my 19 Sierra to add footwell lighting this is what I came up with. These are not the same as my 18 silverado was at all. To get the added led lights I purchased to come on and fade in and out with the overhead lights I had to tap into the BCM connector #1 pin 23 which is a grey wire. The lights look awesome and you can see now. 

61EBB9FF-CD5D-43CE-BDCC-7C1CAFD3C2D9.jpeg

0FC62574-75AD-42DB-A857-F59CD79D7CBC.jpeg

F95CF18A-81A6-4B4B-828F-E572364EFE11.jpeg

Where do I find that grey wire to tap into?

I just got the aura kit and want to hook up the lights to activate with the doors as well. 

kodiakdenali Enthusiast

kodiakdenali

Posted
Posted
14 hours ago, bstraty said:

Where do I find that grey wire to tap into?

I just got the aura kit and want to hook up the lights to activate with the doors as well. 

Its on the BCM wiring harnesses. look up under the dash on the driver's side, on the left side wall of the body there's a box with a bunch of wire harnesses plugged into it (7 of them). that's the body control module.

Connector X1 ("natural" color, so kind of a white/off white color, if memory serves its the connector farthest towards the rear of the truck, but there is a label on the BCM case which identifies the connectors, each one is a different color) pin 23, gray wire.

 

keep in mind this wire also provides a dimmer signal to perform the interior lights dimming. its likely a PWM (pulse width modulation) which means if you connect a relay directly to this as the lights dim on or off the relay will likely engage and disengage very quickly making an unpleasant buzzing sound (the chatter previous posts are talking about)

to solve this you will either need a filter as described so the relay gets a more consistent power, or use a solid state relay. either of those solutions will not allow the floor lights to dim the way the overhead lights will, but that's not a big deal. another option would be to drive your added interior lights with a transistor, which should solve the noise and still preserve the dimming. that's the route I'm going to go (I have a relay on them right now, but it was temporary solution). although doing that would require a tad of electronics know-how.

  • Thanks 1
Daryl Casey Enthusiast

Daryl Casey

Posted
Posted
On 2/7/2020 at 10:03 PM, DNTBL8 said:

Thanks!  does anyone know what gauge wire is the grey wire to the BCM?  I want to tap in with a Posi-Tap, they make them in 20-22 gauge, does that seem right or so it 18 awg? 

I used a RED Posi-tap (18-22ga per the packaging) and it worked with no issues. 

  • 2 months later...
LS6TT New Member

LS6TT

Posted
Posted
On 2/20/2020 at 3:53 AM, Smoothbassman said:

Your close

You will need to use constant 12v power since the accessory power isn't on until you turn the truck on.

Also you will need a filter on the relay input to have the relay fully lock up thru the dimming action for the dome light circuit.

dc65b86c95fd9b1474664d36ab805658.jpg

Sent from my SM-N960U1 using Tapatalk
 

Can you link to the filter you reference?

 

I tapped the grey wire for some under door lighting and while they aren’t flickering when they first come on, they turn off and then back on and so do the dome lights. 
 

figure the filter will fix that?

 

 


 

  • 10 months later...
BlaineBug Enthusiast

BlaineBug

Posted
Posted (edited)

Apologies in advance for reviving an old thread - but is there any concern with tapping into the ambient mood lighting?  I bought some LED strip lights, installed them, tapped into the mood lighting +12 volts under the passenger front footwell and added an in-line 5 amp fuse as well.  Seems to be working as intended.  The lights don't draw much power, obviously less than 5 amps as that's the smallest fuse I had on hand.  I did not use any relays.  These lights originally come with a cigarette plug that I chopped off.  The LED control box has a 12 volt input so there aren't any transformers in the cigarette plug that one would need to keep.  The wires in the wire harness for these LEDs are so insanely tiny there can't be any way the amperage is remotely concerning, my opinion of course.  Installed in a 2019 Yukon.  Tapped right into the ambient mood lighting harness +12 volt wire directly below the glove box.  Lights turn on and stay on when it's dark (which is determined by the light sensor and NOT controlled by the headlight switch) when the doors are opened or the vehicle is running.  Which is what you'd want as there's not much of a reason to have them on in the daytime.

Edited by BlaineBug

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