MUSB35 USB Charger: Install in Your Vehicle
By BOSS Audio Systems | Life at Full Volume | Published: 2026-10-24
Category: How-to Guides
Install the MUSB35 USB charger in your car, truck, or boat with this step-by-step guide. Learn the correct cutout size, wiring tips, and common mistakes to avoid.
Quick Answer
Install the MUSB35 USB charger by cutting a precise 1-1/8-inch (29mm) hole, routing the 6-foot extension cable to your radio's USB or RCA input, and securing the rubber cover for a weather-resistant finish.
Why the MUSB35 Works for Cars and Boats
The MUSB35 is designed for both automotive and marine use, thanks to its dust-proof, water-resistant rubber cover and UV-resistant construction. This makes it a practical choice for dashboards, center consoles, and boat helm stations where exposure to sunlight or moisture is a concern.
The extension cable is 6 feet long, which gives you flexibility to route it to a rear USB or RCA input on your radio. However, if your radio lacks either input, you will need an adapter or a different power source—a limitation to consider before starting.
Installation Steps
- Step 1: Choose the Mounting Location: Select a flat panel surface at least 2 inches deep behind it. Check that the area is clear of wires, brackets, or structural supports. Mark the center point for drilling. Common mistake: Mounting too close to a metal brace, which prevents the charger from seating fully.
- Step 2: Drill the Pilot Hole: Use a small drill bit (1/8 inch) to drill a pilot hole at your marked center. This keeps the larger hole saw from wandering. Checkpoint: Confirm the pilot hole is exactly centered before switching to the hole saw.
- Step 3: Cut the 1-1/8-Inch Hole: Use a 1-1/8-inch (29mm) hole saw or step bit to cut the mounting hole. Deburr the edges with a file or sandpaper so the rubber grommet seals properly. Common mistake: Using a 1-inch hole saw; the charger will not fit. Measure twice, cut once.
- Step 4: Route the Extension Cable: Feed the 6-foot USB/RCA cable from the mounting hole to your radio's rear input. Use zip ties to secure the cable along existing wiring looms and avoid sharp edges. Checkpoint: Leave a little slack near the radio so the connection isn't strained when you push the radio back into the dash.
- Step 5: Connect to the Radio: Plug the USB end into your radio's rear USB port, or use the RCA adapter if your radio only has RCA auxiliary input. Ensure the connection clicks firmly. Common mistake: Forgetting which input the radio expects; check your radio's manual to select the correct source later.
- Step 6: Secure the Charger: Insert the MUSB35 through the hole from the front. From behind, thread the retaining nut onto the barrel and tighten it by hand until snug. Do not overtighten. Checkpoint: The rubber cover should close freely. If it binds, loosen the nut slightly.
- Step 7: Test the Installation: Turn on your radio and select the USB or auxiliary input. Plug in a phone or USB drive to verify power and data transfer. Close the rubber cover to confirm a dust- and water-resistant seal. Final check: If no power, recheck the cable connection at the radio and ensure the radio is set to the correct input.
Product Details
- MUSB35: Requires a 1-1/8-inch (29mm) cutout and includes a 1.5-inch through-hole mount. You must use the exact cutout size; a larger hole will leave the charger loose, and a smaller one won't fit at all.
MUSB35 - MUSB35: Comes with a 6-foot USB/RCA pass-through extension cable. The long cable lets you reach a distant radio input, but plan your routing path to avoid pinching the cable behind panels.
