Disable Daylight Running Lights (DRL)

This could very well apply to any GM vehicle using the same DRL Module 42767.

I have messed with this problem for a while. Everyone has there method, and I found most of them are stop gap measures that really cause other issues.

If you pull the DRL relay then other intrument features will drop.

If you pull the DRL Module again other instrument features will stop, i.e no PBrake light.

After studying the schematic from the factory shop manual I found the best/cheapest solution is the cut the relay lane on the DRL module circuit board. The nice think about this is that with a little solder you can reenable the DRL feature.

Below is a pic of the mod. The right hand tab of the module were it plugs in, the second from the right most connector is what allows the modele to trip the DRL Relay turning on the head lights. Simple score the pathway just above the silver connector part. You will make to cuts about 2mm apart. Then you want to scrap away the copper material between those two cuts. This breaks the electrical connection just for contacting the DRL relay.

This is simple fix. When you look at your module you will see the pathway. If for somereason you want to reenable the DRL feature, just lightly scrap the connector path so that some copper is exposed and reconnect the two with a little solder. It will not take much and don't go more then 2mm onto the silver part of the connector or it will interfere with the reinsertion of the module.

This is a great writeup. I like how it doesn't interfere with any other truck functions.

I plan to do this mod to my denali but i was wondering if this will also disable the twilight function as well.

Can you explain to me what the twilight function is? The shop manual I have is very specific to a 1998 Tahoe, but if this feature was available in 98 I might be able to verify it affect.

twilight is when the lights turn on at night by themselves so in other words im looking to disable all the auto stuff and have everything manual for my lights.

Or you could just pull the fuse.. I've ran my yukon like that for 2 years with no ill effects.

99denalade said:

twilight is when the lights turn on at night by themselves so in other words im looking to disable all the auto stuff and have everything manual for my lights.

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I am pretty sure this will do it. This is the path that allows the system to turn on the lights via the DRL relay.

I have heard that pulling the fuse works for some vehicles, although I don't feel it is isolated enough. GM/Chevy did not make it easy to disable the DRL feature due it being sold as a safety feature.

I can tell you that I tried the fuse option and although I can't remember exactly what the effects were it did affect other features.

nikel said:

I am pretty sure this will do it. This is the path that allows the system to turn on the lights via the DRL relay.

I have heard that pulling the fuse works for some vehicles, although I don't feel it is isolated enough. GM/Chevy did not make it easy to disable the DRL feature due it being sold as a safety feature.

I can tell you that I tried the fuse option and although I can't remember exactly what the effects were it did affect other features.

Click to expand...

I did just run across this on another forum: Posted on Diesel Place .com by go-dwr:

Here is some info I got off another site for the resistor method I used.

I have read several posts asking for information on how to disable the twilight (auto on) feature on the headlights of 99 FSCs.
I wanted to do this myself so I searched and found several methods of doing it.
This is the easiest. You don't have to take the dash apart or cut any wires. Just a simple in line resistor.
Here it goes:

To disable the auto headlights you need a 1.5K ohm resistor (Radio Shack) and 2 Scotchlok Tap Connectors (Walmart).

First locate the Body Control Module (BCM) which is under the dash, below the steering column. Laying on the floor, this should be visible without removing any dash panels. You should find a purple connector (C3). Unplug it.

Locate the white and gray wires (A4 and A6). I don't remember if white is A4 and gray is A6 or vice versa. It doesn't matter anyway. BTW - there are two gray wires in the connector. The one you want is the one farthest away from the white wire.

Tap the gray wire from the plug (C3) to one end of the resistor and the white wire to the other end. You don't need to cut the wires. Make sure you tape up all wires to prevent a short. You should now have a gray wire coming from C3 tapped to one lead of the resistor and the white wire from C3 tapped to the other resistor lead *. Plug C3 back into the BCM. Start the truck and make sure the lights are off. Throw a dark towel or something over the light sensor on the dash and verify the lights stay off. Try your light switch that has probably never been used and that's it! Takes about 5 minutes.

*You can add a switch here if you want. Just connect one end of the resistor to one of the wires in the connector (doesn't matter which one) and the other end of the resistor to one side of the switch. Then connect a wire from the other side of the switch to the other wire in the connector. This will allow you to turn Twilight Mode on and off.

I found your topic about the DRL mod after years of wanting to do this. The other write ups I found had picture links that were dead, and without the visuals they werent very helpful.

I have a 2000 Old Body Style Denali. From what Im told, everything about it is very similar to the Tahoes and whatnot.

But my question is, where exactly do you find the DRL module? I tried asking my local dealership, and they went on about not tampering with the vehicle electronics and all that. They weren't much help.

Ive tried searching for its location online, but I never find what Im looking for.

If you could point me in the right direction, it would be greatly appreciated!

Im trying to figure this out so I can get some HIDs. I could pull the fuse, but I would like to keep the use of my fog lights.

Also - the way I disabled my auto-on/"twilight" feature, was unplugged the small wiring harness from the back of the mirror. Mine had 2 plugs, one with 2 wires and another with 6. The one with the 2 wires controls the auto-on headlights, and the auto-diming of the mirrors at night. Yellow is headlights, orange is mirrors. So you could cut the one wire if you wished to keep the mirrors, or simply unplug it.

I just unplugged mine, I have 5% tint all around, and headlights behind me at night never give me a problem.

I dont know if all vehicles are set up like mine is (with the wiring on the back of the rear view mirror), but if so, its a very easy way to fix the twilight feature.

I use hids and left the drl function intact. When I had my Panel down lately it was in a gray plastic enclosure taped to the larg harness from the fire wall to the dash unit. Look below. Mine doesn't have auto on. Thinking about adding one.