Dome Light Wiring

Silverado/S10 · April 5, 2009

Hello everyone,

I have some additional exterior lighting that I am putting on my truck and I would really like to have them dim on and off with the interior lights (i.e. entry/exit lighting). The specs on the lights are very vague but I can guarantee less than a 20W draw. I am wondering what the best way to power these lights would be. The dome light is the first thing that comes to mind but I have no idea where to tap into or if I would need a relay (again low power probably not, but just throwing it out there). The other problem I run into is if I tap into an in cab power source how do I get it out to the exterior (engine bay or underside works for me). This truck is much more "sealed" than my s10. In that I just popped up a trim piece and fed it through the pre existing hole in the floor. Anyway, if someone knows of a power source (preferably by the DIC buttons since I know how to remove that panel) that I could use and way to get it out of the cab, please let me know, thanks.

P.S. it's a 2008 lt2 silverado

Silverado/S10 · April 6, 2009

okay, i lied, it turns out it's 23.4W, my bad. Inefficient little LEDs I guess.

Come on does anyone at least have a wiring harness diagram I could look at. Dome over ride, dimmer switch, BCM, something?

[EDIT]: NEW PLAN!!! ignore prior post and title. I noticed today that the reverse lights come on with the entry/exit lighting and stay on until the interior begin to dim(only when it is dark out). For simplicity sake and the fact that the LED's probably wouldn't dim like the other lights anyway. I am just going to hook them up to the reverse lights in the tail lights. I even have a diagram for those. Question is where the wires run so I can splice in since I need power under the truck. I would just crawl up under the truck and look, but we got 4 inches of snow last night (right after I did my Spring detailing).

Cliff notes: Splicing into reverse lights in taillights, need to know which one is easier to get to and where:

brims · April 6, 2009

The wire from the BCM X2 pin 5 goes to the left I/P junction block X1 pin B4 and out X9 pin 8 onto the interior courtesy lamps. From BCM X6 pin 2 it goes to left I/P junction block X12 pin 6 and out X9 pin 6 onto the CHMSL.

These are fed directly from the BCM so I do not know what kind of power they can handle before burning up/shutting off.

TexasAl · April 11, 2009

Use a relay. The interior lights/back up lights may be connected to a module, and the additional draw will probably burn it out.

ScottyBoy · April 11, 2009

What kind of lights are you trying to hook up and where? Also, if you hook them up to the reverse lights, they might only come on when you unlock the doors with the keyless entry, and they will be on every time you put your truck in reverse. Are you sure thats how you want them wired up? They may be a better way, just explain what you are try to do or the end result you'd like to accomplish.

Silverado/S10 · April 12, 2009

What kind of lights are you trying to hook up and where? Also, if you hook them up to the reverse lights, they might only come on when you unlock the doors with the keyless entry, and they will be on every time you put your truck in reverse. Are you sure thats how you want them wired up? They may be a better way, just explain what you are try to do or the end result you'd like to accomplish.

I am putting leds on the frame under the doors that light up the ground when you get in and out of the vehicle.

I noticed that when you unlock the doors with the key fob the taillight reverse lights come on and stay on as long as the interior lights do.

Also, when I turn off the truck, the reverse lights stay on for the amount of time set by the DIC.

These are the only two times I would ever need the lights to be on.

The only downside is that they would be on when I am in reverse. Since that is all of 20 seconds a day and does not happen on public roads (unless I did something wrong) it would be okay.

I figure pulling off one of the taillight or trailer wiring harness connectors at the back of truck (they are all located by the spare tire) splicing in there and reconnecting would be the best way to go about this. I am open to all suggestions though. And to a prior comment, yes I would use a relay if going off the BCM, I though these things drew like 2W of power not 24W when I ask that.

TexasAl · April 12, 2009

What kind of lights are you trying to hook up and where? Also, if you hook them up to the reverse lights, they might only come on when you unlock the doors with the keyless entry, and they will be on every time you put your truck in reverse. Are you sure thats how you want them wired up? They may be a better way, just explain what you are try to do or the end result you'd like to accomplish.

I am putting leds on the frame under the doors that light up the ground when you get in and out of the vehicle.

I noticed that when you unlock the doors with the key fob the taillight reverse lights come on and stay on as long as the interior lights do.

Also, when I turn off the truck, the reverse lights stay on for the amount of time set by the DIC.

These are the only two times I would ever need the lights to be on.

The only downside is that they would be on when I am in reverse. Since that is all of 20 seconds a day and does not happen on public roads (unless I did something wrong) it would be okay.

I figure pulling off one of the taillight or trailer wiring harness connectors at the back of truck (they are all located by the spare tire) splicing in there and reconnecting would be the best way to go about this. I am open to all suggestions though. And to a prior comment, yes I would use a relay if going off the BCM, I though these things drew like 2W of power not 24W when I ask that.

Looks like you are good to go.Your setup should be fine.

brims · April 12, 2009

Also, when I turn off the truck, the reverse lights stay on for the amount of time set by the DIC.

I always think there is some wiring problem with a vehicle whose reverse lights come on any time it isn't in reverse.

Silverado/S10 · April 12, 2009

Also, when I turn off the truck, the reverse lights stay on for the amount of time set by the DIC.

I always think there is some wiring problem with a vehicle whose reverse lights come on any time it isn't in reverse.

doesn't everyone's NBS do that?

or is mine just special

brims · April 12, 2009

doesn't everyone's NBS do that?
or is mine just special

I turned off all that approach lighting.

ScottyBoy · April 12, 2009

It should be fine, just be sure to waterproof/weatherproof all your wiring connections under your truck. Also, don't leave any exposed wiring. Cover EVERYTHING with flexible split wire loom like the factory wiring is. Any exposed wiring can be hit by road debris, rocks, etc. and get cut, or split or something like that and end up creating a short if it touches ground.

Personally, if it were me, I'd make all my connections inside the truck to the interior light wiring then drill a hole as close as possible to where the lights will be mounted to run the wires. Then coat the hole and thw wire passing thru it with a huge gob of silicone to seal it up.