The Baja Designs 640325UP is a universal upfitter wiring harness for the LP9, LP6, and LP4 Pro LED light series. The manufacturer rates it for up to four lights on one harness, with leads that wire into the vehicle's stock upfitter or auxiliary switches. Each lead is rated at 11 amps (140.8 W), so add up your total light draw before committing to a four-light build. Compared with a loose toggle switch on the dash, this approach keeps the lights on the factory switch panel, which gives a cleaner, more integrated look for trail, work-truck, and fleet setups. Long-tail searches for LP9 four-light upfitter harness, Baja LP series aux switch wiring, and LP6 factory switch integration lead to this exact part.
This harness is listed as universal rather than vehicle-specific, so fitment depends on your truck's upfitter circuits and how many lights you mount. LP-series lights operate on 12 to 36 volts, and the manufacturer's LP install sheet identifies a Deutsch DT06-4S connector at the light end. Installation involves cutting and splicing into the vehicle's circuits, so plan on a few hours and basic wiring skills. Owners on user forums report that upfitter wires can be short and hard to reach, so measure your run first. The manufacturer also advises that high-beam and low-beam pins should never be powered together, so check the wiring before energizing the lights.
The manufacturer describes leads designed to wire into the vehicle's stock upfitter or auxiliary switches. Owners on user forums who have done this report trimming the included switch and relay section and feeding the leads to the upfitter circuit, though some recommend confirming the relay and fuse arrangement first.
The manufacturer's LP-series install sheet states that power should not be supplied to the low-beam and high-beam pins simultaneously. The manufacturer also offers separate upfitter lockout harnesses for LP9 and LP6 lights. Confirm with the manufacturer whether this 640325UP includes lockout protection before wiring.
The manufacturer describes its upfitter harness category as designed to connect auxiliary lights to factory upfitter or auxiliary switches, or to aftermarket power management systems such as sPOD. Confirm compatibility with your specific switch panel before purchase.
Expect a moderate DIY job. The manufacturer's upfitter lockout instructions call for a circuit test light or multimeter, pliers, and crimp connectors, and they advise testing the upfitter wire before powering the lights. Owners on user forums report that the included relay and switch section can be trimmed off when the vehicle's auxiliary system already has its own relay and fuse, and that the leads may need to be shortened to reach the switch. Route leads through the engine bay, keep them away from hot and moving parts, and confirm that high and low beam are never energized together.
