Amazing interior light mod!!!

[Ageless]

Only joined to spread the word. Like most of you I've been frustrated with the horrible interior lighting without easy fix. I also wasn't willing to have holes drilled in my trim pieces, or lose any functionality of my switches or courtesy lights. If that's of interest to you, I'll try to include screenshot of item since links die, and hopefully enough pictures to get you through so you don't have to spend multiple hours testing circuits to figure it out. 

 

The good news is the rear dome lights are so easy to do. Take the rear dome assembly down and take it apart. It's only held up with clips and a small pry tool to get it apart.  Remove the 2 fresnel lenses out and put it back together. That's it. Probably 3X the usable light from the rear domes with a nice even spread. 

The front assembly is quite a bit harder. I'm not going to explain how to remove the assembly and take it apart, there's plenty of videos online. For this mod I ordered some neutral white 3/4inch clearance lights from Tecniq. They have a real nice pattern to them and plenty bright. I needed a way to power them so I used some mosfet trigger modules. Probably 10 bucks in parts if I didn't over order for another projects. I needed some diodes to prevent feedback and keep the bcm safe. I had some on hand. DONT FORGET THE DIODES. 

 

I removed the fresnel lenses from the front as well. I took everything apart and with a Drexel 'gently' made the leds fit roughly in the same position as the factory holes. It doesn't take much. I had to trim a bit from the bulbs as well.

There's a tiny spot on the pcb board that produces 4 volts on either side corresponding to the lights. If your not comfortable soldering, it's pretty small. 

 

Next I routed the wires from the led through the holes directly behind them. I did have to cut some of the rubber out, but be careful not to take too much. Once the pcb was back in, I ran the wires towards the rear and again used the Drexel to make room on the back piece for them to come out.

 

Then I wired them to the mosfet modules. You might have to knock the tiny led off of the module. It's a tiny power draw but these module are meant for 5 volts and we're working with 4V.

 

Mosfet module Requires Vin, Gin, Vout, Gout, trigger, and trigger ground. I place the diodes in the the Vout. Make sure the orientation is correct. Module power out to led. Pigtailed Gin to trigger ground. And made some quick disconnect leads for the power in.

 

I connected to power and ground directly to the wiring harness via t-taps. I know people have said you can mess up the bcm that way, but considering the leds only draw 40 mA @12V each I wasn't worried about it. Connected ground to number 5 pin on the grey harness. 

 

I'll have to apologize, I don't remember which wire I connected in the harness for power. It was late and I was very frustrated. I initially connected to number 14 but I lost some functionality.

There was another wire that hade 12v power at all times and I hooked it up there. I believe it was pin number 10.

 

Anyways I hope this helps. I know gm dropped the ball on these truck for interior lighting. Mine are so bright now I have zero issues. Have full view and it's bright enough to see everything. The lights up front don't shine at my eyes, and they light up the floor. I'm not even going to do the floor lamps now! 10/10 upgrade!

 

P.S. I'm going to throw some pictures of the interior up here so you can see the bightness. Don't judge, she's a work truck! Lol 

 

ANMBEST 10PCS DC 5V-36V 15A(Max 30A) 400W Dual High-Power MOSFET Trigger Switch Drive Module 0-20KHz PWM Adjustment Electronic Switch Control Board Motor Speed Control Lamp Brightness Control https://a.co/d/19L4oGi

 

https://www.ebay.com/itm/292380373219

[asilverblazer]

The factory LEDs in the front are only 5volts? 

 

Were brighter 5 volt LEDs not available?

 

I'm considering adding some lights in the rear of our Yukon.

 

 

 

[Ageless]

There are for sure, but you still lose a lot of usable light from those stupid fresnel lenses that direct the light at an angle. Also, they're very tiny lights with back soldering and my skills aren't that good. If you could keep the factory led and angle it 30 degrees and remove the fresnel lens you would have adequate lighting. But I was afraid I'd destroy the board attempting that. Again, my skills with pcb boards aren't that good. 

[Aquanut3]

On 9/22/2024 at 5:42 AM, Ageless said:

 

 

 

 

 

Next I routed the wires from the led through the holes directly behind them. I did have to cut some of the rubber out, but be careful not to take too much. Once the pcb was back in, I ran the wires towards the rear and again used the Drexel to make room on the back piece for them to come out.

 

Then I wired them to the mosfet modules. You might have to knock the tiny led off of the module. It's a tiny power draw but these module are meant for 5 volts and we're working with 4V.

 

Mosfet module Requires Vin, Gin, Vout, Gout, trigger, and trigger ground. I place the diodes in the the Vout. Make sure the orientation is correct. Module power out to led. Pigtailed Gin to trigger ground. And made some quick disconnect leads for the power in.

 

 

 

I'll have to apologize, I don't remember which wire I connected in the harness for power. It was late and I was very frustrated. I initially connected to number 14 but I lost some functionality.

There was another wire that hade 12v power at all times and I hooked it up there. I believe it was pin number 10.

 

Hi @Ageless I Just took delivery on a 2025 Sierra 2500HD and agree with the pathetic lighting and ordered the same Mosfets from Amzn and chose the 11mm flush lights from https://www.oznium.com/led-bolts-prewired-leds/led-bolt

I am handy with electronics but have never wired a Mosfet could you explain where each connection goes? here are my assumptions to confirm

Volt In = 12v source Tap See circle on photo below

Grnd In = Ground tap See circle on photo below

Volt out = Diode to 12v + on LED light

Grnd out = to LED Ground ?

trigger = J1 to the 4v spot you circled on the circuit board? See 2nd Photo circle

trigger ground = Any Ground pig tail wire to ground in connection?

 

Also does the local press to turn on still work?

Does the ramp up/down in brightness still work?

If I wanted to replace the back lamps assume would need to do the same as LEDs are 5v?

Thanks a bunch

 

 

 

 

Edited January 31, 2025 by Aquanut3

[White samurai]

What switches do you have mounted in your headliner and how did you do that ? 

[Raffman]

^{My 2022 Denali (Refresh) doesn't have that style of rear dome light bulbs.  They are just as inadequate though...}