How to hardwire a dash cam
Hardwiring means running a kit from the fuse box or OBD-II port to the dash cam so it gets constant power for parking mode instead of just the cigarette lighter; a kit like the PRUVEEO Smart Acc Hardwire Kit runs $15.99 and a fuse tap install takes under an hour.
The main piece of gear for this job. The rest of what you need is below.
What does hardwiring a dash cam actually do?
A dash cam plugged into the 12V cigarette lighter socket only records while the ignition is on. Hardwiring taps into a fuse that stays live even with the key out, so the camera can keep recording in parking mode: watching the car while it sits in a lot or on the street.
Every hardwire kit does the same basic job. It steps the car's electrical system down to the 5 volts most dash cams use over USB, and it adds a low voltage cutoff circuit so the camera stops drawing power before it drains the starter battery.
What you need before you start
Beyond the hardwire kit itself, a few basic tools make the job go faster and cleaner.
- A hardwire kit rated for your cam's port: USB-C, Micro USB, or Mini USB
- A trim removal tool or plastic pry tool for the A-pillar and fuse box cover
- A test light or multimeter to find a fuse that is hot only with the key on (switched) and one that is always hot (constant)
- Add-a-fuse taps sized to your fuse box, usually included with the kit
- Zip ties or adhesive clips to route the cable
How to hardwire a dash cam (step by step)
- Park with the engine off and disconnect the negative battery terminal if you are not confident working near the fuse box.
- Open the fuse box, usually under the dash or in the engine bay, and use a test light to find one fuse that is hot only with the ignition on and one that is always hot.
- Connect the kit's add-a-fuse tap to the switched fuse for the ACC line and to the constant fuse for the battery-sense line, following the kit's color coding.
- Route the kit's power cable up the A-pillar, across the headliner, and down to the dash cam mount, tucking it behind trim panels as you go.
- Ground the kit's ring terminal to an existing metal bolt on the chassis if the kit calls for a separate ground point.
- Plug the kit's output cable into the dash cam and set the low voltage cutoff to the level you want.
- Reconnect the battery, start the car, and confirm the cam shows parking mode is active with the key out.
Where does the constant power wire actually go?
Most kits use two taps: one on a switched fuse that only carries power with the ignition on, and one on a constant fuse that is always hot even with the key out. The switched fuse tells the kit's internal circuit that the engine is off so it can drop into low power parking mode; the constant fuse is what actually feeds the camera while parked.
An OBD-II power cable, like the Thinkware OBD II Power Cable at $44.99 or the VIOFO OP100 OBD-II Constant Power Cable at $59.99, skips the fuse box entirely and plugs into the OBD-II diagnostic port most cars have under the dash. It is a slower job to route but there is nothing to tap or splice into.
How do I set the low voltage cutoff?
The cutoff voltage decides how much of the starter battery's charge the camera can use before it shuts off. A resting lead-acid battery reads about 12.6V at full charge, 12.4V at roughly 75%, 12.2V at roughly 50%, and 12.0V at roughly 25%. Kits with an adjustable cutoff, like ones with an LED voltage display, typically let you pick anywhere from 11.6V up to 12.4V.
A two-channel dash cam recording in parking mode draws roughly 4 to 5 watts, or about 0.4 amp from a 12V battery. At that draw, the difference between an 11.6V and a 12.4V cutoff can be several hours of parking mode time, so a lower cutoff buys more recording time at the cost of leaving the battery more discharged.
Fuse tap kit or OBD-II power cable: which should I use?
A fuse tap style hardwire kit, like the PRUVEEO Smart Acc Hardwire Kit at $15.99 or the Vantrue 11.5ft USB-C Hardwire Kit at $24.99, is the cheaper and more common route. It requires opening the fuse box and identifying a switched and a constant fuse, which takes a bit more care but gives a very clean, permanent install once the cable is routed and tucked away.
An OBD-II power cable, like the Thinkware OBD II Power Cable at $44.99 or the VIOFO OP100 OBD-II Constant Power Cable at $59.99, plugs straight into the diagnostic port most cars have under the dash instead of the fuse box, so there is no fuse identification step at all. It costs more, and the cable run from the OBD-II port up to the dash cam is often longer than from a fuse box closer to the dash, but it is the simpler choice for anyone who would rather avoid opening the fuse panel.
What you need for this job
Prices change often.
Frequently asked questions
Do I need to cut any wires to hardwire a dash cam?
No. A hardwire kit uses add-a-fuse taps that slide in alongside the car's existing fuse, so nothing gets cut or spliced. You pull the original fuse, insert the add-a-fuse piece with the kit's own fuse in it, and push the assembly back into the fuse box slot. The only cutting most installs need is trimming zip ties for cable routing.
Will hardwiring void my car's warranty?
Tapping a fuse with an add-a-fuse kit is a reversible accessory install, similar to plugging in a phone charger, and it does not touch the manufacturer's wiring harness. Most manufacturers will not deny warranty coverage for it, but if you are worried, ask your dealer's service department before you start, since policies do vary by brand.
Which fuse box fuses are safe to tap?
Look for accessory circuits the kit's instructions list as commonly compatible, such as the cigarette lighter, rear defroster, or accessory power outlet fuse, and confirm with a test light that one is switched and one is constant. Never tap a fuse feeding the airbags, ABS, or engine control unit.
Can I hardwire a dash cam myself or do I need an installer?
Most owners can do it in under an hour with a trim tool, a test light, and the kit's instructions, since no wire cutting is involved. If your car hides the fuse box behind multiple trim panels or you are not comfortable working near the steering column, a mobile installer or audio shop can usually finish the job in about the same time.
What happens if I pick the wrong cutoff voltage?
Set it too high, like 12.4V, and parking mode may shut off after only an hour or two since the battery has less usable range left before hitting that voltage. Set it too low, like 11.2V, and you risk a battery too weak to start the car. Most owners land between 11.8V and 12.2V as a middle ground.
Do I need a separate hardwire kit for each dash cam channel?
No. A single hardwire kit's output cable plugs into the dash cam's own power port, which already handles power for every channel, whether it is a two-channel front and rear setup or a three-channel front, rear, and cabin setup. You only need one kit per dash cam unit, matched to that unit's power connector type.