The Baja Designs Upfitter Harness (part 60-0109) is a plug-and-play harness for the 2025 Toyota 4Runner that links Baja Designs lighting to the truck's factory auxiliary switches. It is meant for owners who want a clean look while using the stock switches to control accessories. Reverse lights, ditch lights, or a light bar can all run from it. Compared with a universal toggle-switch kit that gets zip-tied to the dash, this setup keeps the cabin tidy and the controls factory-style. Its real value is the wiring already in place, so you avoid building a separate switch and power circuit from scratch.
Fitment is listed for 2025-2026 Toyota 4Runner models. Pre-wired switch setups vary by trim, though. Owners on user forums say the TRD Pro and Trailhunter have pre-wired aux switches in the cabin, connected through pigtail adaptors and hookup points in the engine bay and cab. Other owners report that the switches are available as an option on hybrid models but not the non-hybrid Sport Premium, and that a separate adapter pigtail may be needed on some trims. Long-tail searches like "2025 4Runner factory aux switch harness," "6th gen 4Runner ditch light wiring," and "OEM aux switch pigtail upfitter" point to exactly this compatibility question.
The manufacturer lists fitment for the 2025-2026 Toyota 4Runner and describes the harness as built for the factory OEM auxiliary switches. Owners on user forums report that pre-wired aux switches appear on certain trims and that some trims need a separate pigtail adapter, so confirm your truck's switch setup with the manufacturer before ordering.
The manufacturer states the harness supports up to four Baja Designs lighting kits, and the package includes two upfitter harnesses.
Owners on user forums relay that Baja Designs tech support said the 60-0109 ties into the factory connectors with nothing else required. Another owner reported that the instructions had not been updated for the fused, relayed aux setup, so details vary. Check the factory aux fuses in the engine compartment and confirm with the manufacturer before wiring.
Owners on user forums who installed Squadron Sport ditch lights through the pre-wired aux switches describe a fairly simple job. The harness that comes with the lights includes a relay, power cables for the lights, a battery power cable, and a switch cable. With pre-wired aux, you can cut away everything except the light power cables and wire those directly to the pigtail. Test the circuits before mounting anything. The owner's manual places the aux fuses in the engine compartment. Plan for trimming and re-terminating the harness, and check the manufacturer's installation sheet for the specific steps.
