Ben Hinz
- Jan 27, 2022
- 2 min read

OEM+ Auxiliary Light Switch

Installation Vehicle: 2015 GMC 2500HD Denali Duramax

This is an awesome little upgrade for someone looking to add some auxiliary lighting but doesn't want to wreck there dash with holes and switches and retains that beautiful OEM+ style. This switch retains the fog lights button but also adds another button for auxiliary light (Light Bar, Rock Lights) or whatever you need to use a switch with.

To make it even better and easier, Phil Gamboa (@harness_dr on IG) makes a nice plug and play harness for this! Land the pins at the headlight switch plug and at the BCM plug and then run your lead wire to the engine bay and your set! When you use the Harness Dr. Harness, the dash will light up an indicator when the aux button has been activated just like the fog lights, running lights, and headlights! Phil also does an amazing job mark each wire with what color connector, pin location and device it goes into!

Below there are 2 links for selections if you have the BT Diesel Works/WAMS BCM Tuning. The first link you will want to "Enable" the Off-Road light setting. I do not think this need this needs to be done at all but I did it anyway. The next link is for you to change the "Debounce" time, or "How long to press the button". From the Factory you have to press and hold this button for 2 seconds in order to have the off-road lights come on. I set my to 30ms as recommended by BT Diesel Works, and it works perfect. Keep in mind you need to have headlights on in order to have your off-road lights work with this switch. At this time, there is nothing BT Diesel Works can do to change this.

This was also a great opportunity to flip my OBDII Port around. I did this to keep a slicker profile while in use since my OBDII Splitter for my Insight CTS3 makes it stick out a bit more.

Parts List and Installation Video, and other helpful links below!