Cig lighter and DLC off with key mod

Tonimus · Jul 4, 2025

I've got a OBDXPro dongle that I got for programming, but I also like to use it for extra gauges on my phone. As such, I like to leave it plugged in. I also have a phone charger plugged into the cigarette lighter. Thankfully it only took me a minute to realize that these were full-time hot, not ignition hot. Whipped up a little easily removable mod to make it so the DLC and the cigar/cigarette lighter are key on only.

It uses a mini fuse circuit tap, a mini fuse extended fuse holder, and a mini relay. Grounded it to the body bolt right nearby just so I didn't have to find a ground in the box.

Works fantastic, and I can leave everything plugged in.

Amazon.com

Cadillacmak · Jul 4, 2025

Nice, I like that the wiring isn't hacked and you can restore to normal anytime you want.

ORVietVet · Jul 4, 2025

Very nice work indeed. Built a better mousetrap.

Tonimus · Jul 4, 2025

This same mod could simply be placed in the aux power outlet fuse if you have no need to de-power your DLC and want to power down the other outlets.

4silverado · Jul 4, 2025

I replaced the cigarette lighter with a dual USB-A and wired it to one of those fuse taps into the fuse box on the left side of the dash. I made sure that the fuse I used was ign hot.

Tonimus · Jul 4, 2025

I may tap the other front socket into the same circuit as the cigarette lighter and leave the rear cargo one on its own circuit.

ORVietVet · Jul 4, 2025

Tonimus said:
I may tap the other front socket into the same circuit as the cigarette lighter and leave the rear cargo one on its own circuit.

I love it when I can actually see "the lightbulb above the head" flash on when there is a different avenue to approach something.

Tonimus · Jul 5, 2025

ORVietVet said:
I love it when I can actually see "the lightbulb above the head" flash on when there is a different avenue to approach something.

I tested my new 12v to USB power adapter. Draws 3.5 milliamps when not in use. No need to tie in the other outlets. My MagSafe charger and DLC are the only things I need to turn off with the key, so I’m set.

AuroraGirl · Jul 7, 2025

I wish these trucks had the same fuse box feature as the 2000-2005 Lesabre and probably 2000-2005 Bonneville, that have a 3 position fuse for the cig lighters , and each is fused separate, but moving the fuse over into 2 of the 3 slots makes its key on or always on

Mikloangelo · Jan 31, 2026

So i did something similar to this. But it leaves the cigarette lighter hot but makes the Aux power keyed. Worked out good for me. I just did what was in this video.

Im not sure if it works on all years, But it worked for my 2001 2500HD.

Cadillacmak · Jan 31, 2026

Mikloangelo said:
So i did something similar to this. But it leaves the cigarette lighter hot but makes the Aux power keyed. Worked out good for me. I just did what was in this video.

Im not sure if it works on all years, But it worked for my 2001 2500HD.

Dude, thanks for posting. I need to do this in my wife's Yukon

Mikloangelo · Jan 31, 2026

Cadillacmak said:
Dude, thanks for posting. I need to do this in my wife's Yukon

You're welcome. Pretty simple to do. Just need an inline fuse and some of the terminal ends. Careful you don't short out the pins. Happened to me and blew a fuse on the driver's fuse box.

5202500HD · May 29, 2026

Mikloangelo said:
So i did something similar to this. But it leaves the cigarette lighter hot but makes the Aux power keyed. Worked out good for me. I just did what was in this video.

Im not sure if it works on all years, But it worked for my 2001 2500HD.

So my 06' just has 2 lighter ports. will this mod affect both or just 1? Also does it cut full time power to anything else? Thanks

Mikloangelo · May 29, 2026

5202500HD said:
So my 06' just has 2 lighter ports. will this mod affect both or just 1? Also does it cut full time power to anything else? Thanks

Honestly I dont know how the 03+ model differ. The video title shows 99-03 models. But again not sure. As far as anything else it affected there was nothing else that I saw that the mod changed other than my cigarette lighter ports

Tonimus · May 29, 2026

5202500HD said:
So my 06' just has 2 lighter ports. will this mod affect both or just 1? Also does it cut full time power to anything else? Thanks

Mine also has two ports, but one is a 12v outlet and one is a cigarette lighter. This only changes the cigarette lighter port and DLC. It leaves the other auxiliary power outlets alone. But the same can be done with their power source.

5202500HD · May 30, 2026

Mikloangelo said:
Honestly I dont know how the 03+ model differ. The video title shows 99-03 models. But again not sure. As far as anything else it affected there was nothing else that I saw that the mod changed other than my cigarette lighter ports

Ok so under the hood on drivers side main fuse/relay box I have a 15AMP Cig. Lighter Fuse and a 20amp Aux. fuse. What I'd like to do is ONLY modify the Aux. power outlet to turn OFF with the ignition and leave the Cig. outlet the way it is. Any thoughts/guidance? Thanks all.