How to Install Truck Bed LED Lights
Wire and mount waterproof 12V LED strip lights under pickup truck bed rails with an inline fuse and dedicated rocker switch for bright cargo lighting.
- Read the tools, materials, safety notes, and steps below for free.
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🧰 Required Tools & Equipment
- ✓ Wire stripper and crimper tool
- ✓ Heat gun or mini butane torch
- ✓ Cordless drill with step bit
- ✓ Multimeter or 12V test light
- ✓ Microfiber cloth
📦 Materials & Supplies
- ✓ Waterproof 12V LED light strips (IP67/IP68)
- ✓ 16-gauge primary automotive wire (red and black)
- ✓ Waterproof inline fuse holder with 5A fuse
- ✓ Waterproof rocker switch
- ✓ Heat-shrink butt connectors and ring terminals
- ✓ Rubbing alcohol (isopropyl)
- ✓ Adhesion promoter and zip ties
⚠️ Safety Checkpoints & Warnings
- • Disconnect the vehicle's negative battery terminal before tapping into 12V power sources.
- • Install the inline fuse within 12 inches of the 12V power source to prevent wire fires in case of a short.
- • Ensure all exterior wire splices use adhesive-lined heat shrink to prevent water intrusion and corrosion.
📋 Step-by-Step Guide (6 Steps)
Clean and Prep the Bed Rail Underside
Locate the flat underside channel of both bed rails where the LED strips will mount. Thoroughly wipe the metal surface with isopropyl alcohol on a clean microfiber cloth to remove road grime, oil, and wax. Allow the surface to dry completely for two minutes, then apply adhesion promoter along the strip path.
- • Clean, matte surface visible under the inner bed lip with zero dust or grease residue.
- • A clear, thin sheen of dry adhesion promoter along the length of the rail.
- • Applying LED adhesive directly over dusty paint or bedliner spray.
- • Sticking lights to textured bedliner where adhesive tape cannot seal flat.
Mount the LED Light Strips
Peel back 6 inches of the adhesive backing from the light strip at the tailgate end. Align the strip firmly against the flat underside of the rail, pointing the LEDs downward into the bed. Press down firmly inch-by-inch while slowly removing the rest of the backing paper along the entire rail.
- • LED strips run straight and parallel under the bed rail lip.
- • Tape backing fully removed with no drooping or bubbling along the strip.
- • Peeling the entire backing off at once, causing the strip to tangle or stick prematurely.
- • Stretching the flexible PCB strip, which cracks internal solder joints.
Drill and Mount the Rocker Switch
Choose an accessible spot near the tailgate or inside a rear bed pocket for the switch. Drill a pilot hole, then enlarge it with a step drill bit to match the switch diameter. Deburr the hole and push the waterproof switch into place until it clicks firmly into the cutout.
- • Clean circular hole with no jagged metal flashing.
- • Switch sits flush against the bed wall with the rubber weather boot aligned.
- • Drilling without checking behind the panel for factory tail light wiring.
- • Drilling the hole oversized, causing the switch to spin or fall through.
Route and Join Strip Wiring
Route the power and ground leads from both LED strips toward the switch location, securing the wires behind factory bedside pillars using zip ties. Strip 1/4 inch of insulation from the wire ends and join both strip positive wires together, and both negative wires together using heat-shrink butt connectors. Apply heat until adhesive oozes from connector ends.
- • Wires neatly pulled tight against the body structure, tied every 12 inches.
- • Translucent heat-shrink tubing tightly shrunk over crimped barrels with glue visible at edges.
- • Leaving dangling wire loops that can catch on cargo loading in the bed.
- • Under-crimping, allowing wires to pull out of the butt connector.
Connect Power, Fuse, and Ground
Crimp an inline fuse holder with a 5A fuse into the main 12V positive feed line connected to either the 7-way trailer plug 12V auxiliary pin or a fused battery line. Connect the fused 12V line to the switch input, the LED positive to the switch output, and terminate all grounds to a clean chassis grounding bolt with a ring terminal.
- • Ring terminal bolted flat against bare, unpainted chassis metal.
- • Waterproof fuse holder installed and closed within easy reach near the power source.
- • Grounding to a painted bolt without sanding down to bare metal.
- • Inserting the fuse before all wiring connections are completely finished.
Test Operation and Finalize Weatherproofing
Insert the 5A fuse into the holder and reconnect the vehicle battery. Flip the bed switch to 'ON' to verify that both LED strips light up instantly and evenly along their entire length. Inspect all wire looms, tuck excess slack behind taillight cavities, and secure loose sections with exterior-grade zip ties.
- • All LEDs across both strips illuminate bright white without flickering.
- • No exposed or drooping wires anywhere in the truck cargo area.
- • Leaving the fuse compartment unsealed against road spray.
- • Ignoring individual dead LED sections caused by crimped wiring.
Credit: inspired by an original tutorial by ChrisFix — watch the original on YouTube.
Don’t have everything?
- No Heat gun? Lighter or mini torch held 2 inches away from heat shrink
- No Step drill bit? Standard twist drill bit sized to the switch diameter
- No Adhesion promoter? Double-sided outdoor acrylic mounting tape (3M VHB)