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T1 Dome Light Tap Wires


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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 Silverado. I need to get this done. This was so simple on the 2014s. 4d2a32151a2431b57f5e4566f8f66dc5.jpg

 

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Ok after testing most of the wires in the BCM I finally found the one that I need to make this whole thing come together.

Pin 10 on the forward most BCM connector gives me the positive output for the dome lighting.

After testing the Opt 7 lights I found that I can't turn the courtesy lights on without the main light controller on so I'm going to have to rethink the electrical. I'm currently running it on accessory power and that's not going to work. I need the power to come on when I open the door, and be active when I'm rolling down the road. Going to have to add some relay logic to get this thing working the way I want.

More to come this week. 714cb6264c7b2b90406871def400f4cd.jpg

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I’m in the same boat, wanting to do this for footwell . I believe there is a grey wire in the bcm not 100%. Another option is the dome light wire in the driver A pillar. 
Crazy thing is I checked the A pillar and all of the wiring has been rerouted in the T series trucks. Nothing there but an airbag. They might have taken it thru the B pillar. Don't want to have to tear that all apart.

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4 hours ago, Smoothbassman said:

Ok after testing most of the wires in the BCM I finally found the one that I need to make this whole thing come together.

Pin 10 on the forward most BCM connector gives me the positive output for the dome lighting.

After testing the Opt 7 lights I found that I can't turn the courtesy lights on without the main light controller on so I'm going to have to rethink the electrical. I'm currently running it on accessory power and that's not going to work. I need the power to come on when I open the door, and be active when I'm rolling down the road. Going to have to add some relay logic to get this thing working the way I want.

More to come this week. 714cb6264c7b2b90406871def400f4cd.jpg

Sent from my SM-N960U using Tapatalk
 

What about the ambient light circuit, I believe that’s on with door/remote and stays on while in motion? Also is this harness under the drivers side ?

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What about the ambient light circuit, I believe that’s on with door/remote and stays on while in motion? Also is this harness under the drivers side ?

Yes. It's the harness under the drivers side dash.

 

I really don't like tapping into wires in the BCM, but there's no way around it on this truck. Even found that the new dome lights are solid state on a circuit board when removing the center overhead panel. No way to tap in without knowing how to do surface mount soldering.

 

I'll have to test that ambient light circuit.

 

What's crazy is all of the wiring for everything is already there for features my truck doesn't have like the automatic dimming mirror and the homelink connection. It's even currently powered up.

 

Now only if I can find a wrecked T1 in a salvage yard. I will be racking up on some parts. 446e6b41f614082faf3e6921b5193d7d.jpg

 

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15 hours ago, Smoothbassman said:

Yes. It's the harness under the drivers side dash.

 

I really don't like tapping into wires in the BCM, but there's no way around it on this truck. Even found that the new dome lights are solid state on a circuit board when removing the center overhead panel. No way to tap in without knowing how to do surface mount soldering.

 

I'll have to test that ambient light circuit.

 

What's crazy is all of the wiring for everything is already there for features my truck doesn't have like the automatic dimming mirror and the homelink connection. It's even currently powered up.

 

Now only if I can find a wrecked T1 in a salvage yard. I will be racking up on some parts. 446e6b41f614082faf3e6921b5193d7d.jpg

 

Sent from my SM-N960U using Tapatalk

 

 

 

thanks, all good information here, extremely helpful with future options of adding upgrades. im going to look into the bcm connection this evening see what i can gather, i really want to find that dome wire lol

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The dome wire is a gray wire in the passenger A pillar, but be careful, there are two gray wires in the wire loom.  I installed a set of led light strips under the doors that have running lights in them and also a set of white lights that will illuminate each time a door opens.  

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Ok,

In order to get the OPT-7 Lights to work properly the system has to be powered on when the door tigger switch is activated. I think this is a poor design, and I hope they fix that in future versions. That aside, this is a 10 dollar fix for this situation, and allows you to run the courtesy lights, as well as get the lights turned off automaticaly when you leave the vehicle using a couple of relays.

I finally got everything bench tested and really for final installation in the truck. Heres the explanation on it

83a15ab4cf5827c722871773e5148432.jpg

Legend

Pin 1 - Constant Power
Pin 2 - Switched Power
Pin 3 - Door Trigger
Pin 4 - Relay Power Bridge
Pin 5 - Opt 7 Power Output
Pin 6- Ground
Door- Door Switch Power Relay
Running - Accessory Power Relay

So at a high level when the door relay is idle it passes current to the accessory relay thru the normally closed pin to the accessory relay which closes that switch. If there is no accessory power on the lights don't come on.

Once the door opens it closes the door relay and opens the running relay and the lights turn white.

Door closes and I turn on the truck, the running relay is now powered passing power direct to the lights and they turn back to the preselected color that you set.

Bench tested this setup and it works great. Going to install on the truck this week.

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Installed it today.

Works perfectly!!

I have to add a filter and capacitor to stop the relay from buzzing due to the dimming feature of the lights dropping the voltage below the needed 12V to lock up the relay constant power relay.

Video link below.



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  • 3 months later...

This is incredibly awesome post. Very cool that you figured it out ? for your needs going down the road. However, I am now a bit confused on how to accomplish my simple mission when I began searching this thread...

 I just want a simple set of foot-well lights ( two simple LED strips) to come on when the doors open and go off when the doors shut.  Which wire would I tap into for that, I plan on using a T-tap near the harness. Would that be ONLY pin 10 for my needs?

 

Also if I may rant as a newbie to the forum (GM truck guy my whole life)- It is totally bogus that the lighting in the T1 is not only extremely limited, but focused to one spot-. with jet black interior I can't find anything at night in the floorboards!

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This is incredibly awesome post. Very cool that you figured it out [emoji106] for your needs going down the road. However, I am now a bit confused on how to accomplish my simple mission when I began searching this thread...
 I just want a simple set of foot-well lights ( two simple LED strips) to come on when the doors open and go off when the doors shut.  Which wire would I tap into for that, I plan on using a T-tap near the harness. Would that be ONLY pin 10 for my needs?
 
Also if I may rant as a newbie to the forum (GM truck guy my whole life)- It is totally bogus that the lighting in the T1 is not only extremely limited, but focused to one spot-. with jet black interior I can't find anything at night in the floorboards!
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.

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