Introduction: Adding a Hidden Dash Cam

About: Love using my 3D printer as a tool for DIY, not just printing trinkets.

This project will guide you to installing your own dash cam with a professional looking finish!

It's very simple to power your dash cam with the "cigarette lighter" 12V port or with a USB port in your dashboard, but this leaves wires trailing all over the place, and means that you then can't use that port for anything else.

If you already have a setup like this, or want to install a new dash-cam neatly, then this step by step guide is here to show you the way!


All items in italics are likely supplied with the dash-cam you purchase
  • Dash-cam (or an old phone with dash-cam app installed)
  • Long wire to power dash-cam
  • Dash-cam mount
  • Box type 12V to 5V converter (pictured: step 1)
  • "Piggy back" fuse adaptor (pictured: step 4)
  • Heat shrink tubing
  • Grounding washer


  • Snips
  • Lighter
  • Wire stripper (optional)
  • Multimeter (optional)

Step 1: Getting 5 V Power

First, we need to power the dash-cam, and for this we'll be taking 12V power from the fuse box and running it through our voltage converter.

It's best to use a fuse that powers on with ignition of the car. That way the dash cam should automatically come on when you start the car. You can find an appropriate fuse by reading the car's manual, then check it with a multimeter (optional).

Step 2: Owner's Manual Checking

Look through your owner's manual (or a Haynes manual) for the fuse box section, probably in a group with the rest of the electronic systems. There should be a diagram that has a picture of the fuse box and has a list of what fuse is for what circuit. This may also be written on the back of the fuse box cover. Pick a fuse that will come on when you start the car, but don't pick something that is safety critical just in case you make a mistake.

Some good candidates are:

  • Window control
  • Wipers
  • 12v Utility socket
  • Screen Wash pump


  • ABS or any other braking device
  • Transmission
  • Fuel pump
  • Airbags
  • any other device that is critical to the safe functioning of the car

Step 3: Multimeter Checking (optional)

Set your multimeter to DC voltage. Put one probe on a metal part of the body (as the whole of the car body should be grounded). Put the other probe on the small metal contact you can reach through the fuse. Check that the meter reads 0V. Now turn on the ignition to power the electrical system, and the multimeter should read 12V.

If it doesn't, check that you've got proper contact on the fuse (as this can be a little tricky sometimes). You can do this by swapping the multimeter to continuity mode. You'll know you're in continuity mode by touching the probes together and listening for a *beep*. Now put the probes on either side of the fuse and you should hear the same *beep*.

Step 4: Adding the Piggyback Fuse

Remove the fuse you identified in the last step, and put in the piggyback where it used to be. Now put the same fuse in the top of the piggy back adaptor. You should now have a 12V power line which you can check again using the multimeter method described previously.

Step 5: Adding Ground (0V)

We have 12V, and now we need a ground (0V). Get a wire to join anywhere on the metal bodywork of the car. You should be able to trap the end of the wire behind a nut.

Step 6: Connecting Voltage Converter Box

Now connect the 12V line and ground to the 12V and 0V inputs on the voltage converter box. You can do this in a number of ways, I'll use twisting and heat shrink as this is the easiest to do in a car.

Push a section of heat shrink tube over one of the wires you want to join. Spread out the ends of the wires and push them into each other. Twist them together so they won't come apart, slide over the heat shrink and use a lighter to shrink it.

Step 7: Mounting the Camera

Put the dash-cam in the mount, and attach it to the car. A good spot is behind the rear view mirror. Make sure you turn it on and check that the picture is good. You should be just able to see the bonnet in the bottom of the frame.

Step 8: Establish Cable Length/routing

Attach the power cable to the dash-cam and begin routing it back to the fuse box. You can push it into the roof liner to hide it, behind door seals and into other crevices. It's a good idea to check how the cable routing looks from the outside of the car too.

Step 9: Connecting the Dash-cam to Power

Cut the cable so that you have a bit of leeway to connect to the voltage converter box. There should be a red and black wire within the insulation tubing. Peel back around 5 cm of insulation, and strip the ends of the two wires inside with a stripper (if you don't have one, you can use a knife carefully).

Connect the red wire to the 5V output and the black to the 0V output as described in the previous instruction.

Step 10: Tidy Up!

Double check that the camera is powered when you turn the ignition on. Tidy up the fuse box and put the cover back on.

Congratulations! You're finished!

Step 11:

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