How to Hardwire Your Dash Cam

What is hardwiring?

Hardwiring is the process of connecting a hardwire kit to your vehicle’s fusebox. The hardwire kit enables users to power on devices such as a dash cam. Instead of plugging a dash cam into a constant 12V cigarette outlet, a hardwire kit protects your vehicle from battery discharge and provides constant power even after turning off your vehicle.

What do I need to Get Started?

To get started, you will need:

  • Hardwire Kit

  • (x2) Fuses

  • (x2) Add-a-fuse

  • Crimping tool

  • Multimeter

  • Needle nose pliers


The Complete Guide

Before starting, there are a few things you should make a note of to successfully install and setup your hardwire kit.

  1. It is strongly recommended that prior to installation, your vehicle’s battery is in good health.

  2. The fuses you will use may differ from vehicle to vehicle. We recommend purchasing a set of different fuses.

  3. The add-a-fuse will correspond to the fuses you will be using. We recommend holding off purchasing them until you determine which fuses you will use.

WARNING: Improper installation and handling may cause serious damage to your vehicle. GRDIAN is not liable for any mishandling and damages resulting from this guide. Install at your own discretion. Consult your car technician if you continue to have issues. GRDIAN cannot provide help, instructions or recommendations beyond this guide. Please follow each step accordingly to ensure safe installation.


Step 1: Locate Your Fusebox and Battery

Battery

Locate the battery with your vehicle’s user manual. If the user manual does not provide this information, you can simply search for it online. Hint: The location of the battery is typically located in the engine bay or in the trunk.

Fuse Box

Locate the fusebox with your vehicle’s user manual. If the user manual does not provide this information, you can simply search for it online. Hint: The location of the fuse box is typically under the driver’s steering wheel, passenger’s glove box or in the trunk. If your vehicle has multiple fuse boxes, choose one that is easily accessible.

2012 - 2018 BMW f30 3-series Fuse Diagram for 320i, 328i, 335i, 340i, 330e, M3
2017 BMW f30 3-series 330e Fuse box and Battery Location

Step 2: Test Your Car Battery’s Health

Tools needed for this step:

  • Multimeter

A healthy car battery will not only ensure that your vehicle is running properly, but also ensure that your hardwire kit and dash cam will perform as it should.

To get an accurate reading of your battery, we recommend letting your vehicle sit idle for at least 1 hour to get a “resting voltage”. A healthy battery should read 12.6V or 24.6V. If your battery reads below 11.6V or 23.6V, the hardwire kit may not work properly.

Using Your Multimeter to Test Your Car Battery

  1. Plug your black and red lead into your multimeter and set it to 20DCV.

  2. Use the black led to touch the negative ( - ) terminal of your battery and the red lead to touch the positive ( + ) terminal of your battery.

  3. Make note of the reading.


Step 3: Locate and Test a Ground Point

Tools needed for this step:

  • Multimeter

Grounding your wire is crucial to the safety of yourself and your vehicle in the event of a short circuit. The chassis of your vehicle generally makes a good ground. However, vehicles today are built with a combination of metals, spot welds, glued together uni-body panels and isolated chassis components. Therefore, we cannot assume that a good ground will automatically be on the chassis.

In most vehicles you should be able to locate an obvious ground near the fuse box. There are 2 ways to test for a proper ground.

Continuity Test

  1. Set your multimeter to Continuity Test or 200 ohms.

  2. Using the black lead, touch the negative terminal of your vehicle’s battery and then place the red lead on to your ground point. Your multimeter should beep if it is a complete path. If it does not beep, look for another ground.

Resistance Test

  1. Set your multimeter to Resistance Mode or Diode Check.

  2. Using the black lead, touch the negative ( - ) terminal of your vehicle’s battery and then place the red lead onto your ground point. A good ground should read less than 0.2 ohms.


Step 4: Determining Constant and switched fuse

Tools needed for this step:

  • Multimeter

What’s the difference between a constant and switched fuse? A constant fuse will show power even when the vehicle is turned off. A switched fuse will only show power when the vehicle is turned on. We will be using both constant and switched fuse to connect to our hardwire kit. Hint: Some vehicles maintain power a couple minutes after being turned off. We recommend opening your doors/trunk and let it sit for ~30 minutes. Upon returning, avoid opening/closing any doors or turning on anything.

NOTE: Avoid using fuses over 10A and fuses that are relative to car safety (brake lights, cooling fan, ECU, SRS, etc).

Constant Fuse

  1. Set your multimeter to 20 DCV.

  2. Use the black lead to touch your vehicle’s chassis or your ground point.

  3. Place the red lead on each ends of the fuse to test. If your multimeter reads 12V, it is a constant fuse.

Switched Fuse

  1. Set your multimeter to 20 DCV.

  2. Use the black lead to touch your vehicle’s chassis or your ground point.

  3. Place the red lead on each ends of the fuse to test. If your multimeter reads ~0V, it is a switched fuse.


Step 5: test for Line & Load Side

Tools needed for this step:

  • Multimeter

  • (x2) Add-a-fuse

Once we’ve determine a constant and switched fuse, we will test which side of the fuse is line and load. This is an important step to take to ensure that we insert the add-a-fuse in the right direction.

Testing for Line & Load Side

  1. Set your multimeter to 20 DCV.

  2. Remove either your constant or switched fuse and insert the add-a-fuse into the empty slot.

  3. With the black lead touching your ground, test for line side by placing the red lead on the bottom left slot of your add-a-fuse. It should read 12V.

  4. Test for load side by placing the red lead on the bottom right slot of your add-a-fuse. It should read 0V.

  5. If the above is true, your add-a-fuse is placed in the correct position. If not, placed the add-a-fuse in reverse and test again.

  6. Repeat the above steps for the other fuse.

line and load fuse

Step 6: How to Use your add-a-fuse

Tools needed for this step:

  • (x2) Add-a-fuse

  • (x2) Old Fuse

  • (x2) New Fuse

Inserting the Correct Fuses Into Your Add-a-fuse

  1. Remove one of your add-a-fuse from their slots and remember their orientation.

  2. Insert the original fuse at the bottom of your add a fuse.

  3. Insert the new fuse at the top of the add-a-fuse.

  4. Re-insert both add-a-fuse into their correct slot and orientation.

  5. Repeat the steps for the other add-a-fuse.

Note: The new fuse must be a lower value than the original fuse.

how to add the correct fuses into your add-a-fuse

Step 7: Connecting Your Add-a-Fuse to Your Hardwire Kit

The final step is to connect all the pieces together.

BATT+ (Yellow)

  1. Attach the BATT+ (yellow) wire to your add-a-fuse by using a crimping tool.

  2. Once attached, plug the add-a-fuse into your constant fuse. Make sure to insert the add-a-fuse in the right direction with the load side to load side.

ACC+ (Red line)

  1. Attach the BATT+ (yellow) wire to your add-a-fuse by using a crimping tool.

  2. Once attached, plug the add-a-fuse into your switched fuse. Make sure to insert the add-a-fuse in the right direction with the load side to load side.

GND (Black)

  1. Secure the GND wire to your ground point.


Step 8:

The Charger Plus is equipped with voltage protection settings to help minimize battery discharge by cutting off power output to the dash cam when the voltage drops below the set threshold.

How do I setup a value that fits my vehicle?

  1. With the dash cam unplugged, use a multimeter to check your vehicle’s battery voltage. Do so when the engine has been shutoff for 5~10 minutes. Take note of the voltage.

  2. Now measure the voltage with the dash cam plugged in. Your engine should still be shutoff. Note the voltage.

  3. Set the Voltage Protection Setting based on your findings. For example: If the multimeter detects 12.5V without the dash cam and 12.2V when dash cam is plugged in, you should set the voltage setting to 12-11.8V at least 0.2V lower when the dash cam is plugged in.

NOTE: Make sure you set the correct voltage setting or your dash cam may keep rebooting.