Audi A3 Hardwired Dashcam

Hardwiring a dashcam in my Audi A3

I had to hardwire my Nextbase Dashcam in my Audi A3. I’ve owned the car for about a year now, I had some free time, and it’s a job that’s been annoying me. Thought I may aswell make use of the free time and crack on with it, since it’s an easy job.

 




My previous car had a DPDT switch fitted, so I could run it off a permanently live when I was shopping, and a switched live when I was driving.

I have plans for a more OEM design using the dashboard buttons, although I have to either have a button custom made, or see if I can find one that suits me.

I didn’t write a guide on how to install the dashcam in the Audi, because I just wanted to complete a job I’ve been meaning to do. So here’s a few points if you intend on hard wiring the dashcam yourself.

All dashcam hardwiring kits (or next base ones at least). Need a source of power, and a source of ground. Here’s the basic run down on installing your own dashcam hardwiring kit, and then a quick post at the end specific to the Audi A3

Using a multimeter for finding feeds for Hardwiring

This procedure is virtually the same for almost any car, like I mentioned above. Dashcam hardwiring kits are really simple to install and don’t require much in terms of wiring. They basically just need a power and a ground. If you aren’t sure on how to do it, here’s a basic run down below

I’ll assume you know the basics of how to read a multimeter and using it

Finding a power feed with a Multimeter in a Car

To keep it simplistic (for purposes of this post), there are two sources of power on a car. There is a permanent live (which is always 12v whether keys are in ignition or not), and there is a switched live (which is only 12v when the keys are in ignition and it’s “on”).

This is down to preference, but most people tend to use a switched live for a dashcam. Unless you have an intelligent dashcam unit with power saving features, wiring to a permanent live can drain your cars battery if left for a while.

The procedure is in itself, is very similar. So here’s how to do it:

Place the multimeter into DC voltage (20v max). Push the multimeter negative probe to a car earth (normally push the probe between the gap in the door hinges). Using the positive probe touch the terminals of the fuses on the car with the ignition OFF.

Anything which shows 12v is a permanent live, if the fuse shows 0v, turn the ignition ON and check the voltage again. If it only shows 12v when the ignition is on, that’s a SWITCHED LIVE supply.

Now, when you’re hardwiring a Dashcam, you have to take into consideration the fuse you are using. I normally try to resort to using a “non-critical” car system. The fuse tap itself functions so if the fuse belows, it should only take out the dashcam. However if you’ve tapped the fuse wrong (or you’re unlucky), it can take out the fuse on the circuit it’s on.

As a general note, the easiest fuses to go for are ones that you can do without in the event of a failure (heated seats, rear wipers, air conditioning, cigarette lighter, etc). The fuses to go for are usually 5A maximum. The best way to identify them is to first have a look through the owners manual, or the fuse cover guide to see which fuses are possibilities. Anything talking about safety (Lights, ABS, ECU for example, leave alone). 

It’s just now worth it.

Now, you’ve read this procedure and found your relevant power feed that applies to fitting your switched live power source for your Dashcam. The next step is a ground source

Finding a ground feed with a Multimeter in a car

Put your multimeter into continuity mode, and touch your probes to make sure you have a working ground system.

Now the easiest way is to just look for a nut/screw that is fitted to the car. Metal on metal usually means ground when it goes to a car. Just make sure it’s not plastic behind

Touch the screw with the positive multimeter probe, as long as it beeps, you have a ground connection. If it doesn’t beep, it means you don’t have a ground.

Once you’ve found your ground you then just need to route the cabling and wire up the fuse tap and fit the ground cable to the screw. Your car is then hardwired together

Also, make sure you fit the fuse tap the CORRECT way around. The fuse which has the wire coming out of it should be the dashcam, the original fuse fitted should be in the first slot. If you reverse the fuses, it means if your dashcam blows, it takes out the power to the other circuit fitted to it. Whereas putting the original circuit there first, it means if your dashcam goes, the original circuit still functions.

Quick install guide for Audi A3 hardwired Dashcam

  • Remove the side pillar trim (pull it away and upwards towards the roof)
  • Run the cabling under the roof lining
  • Using tape to hold the cabling on the A3 A-Pillar trim
  • Feed the cabling through the hole where speaker wire runs
  • Attach the ground connector cable (I used the 8mm holding the footwell cover)
  • Attach the power feed (I used a micro-blade on Fuse 4 for the Aircon)

This is then the Dashcam hardwired, turn the ignition to live and make sure your Dashcam powers on. Once it powers up, take the keys out of the ignition. If the Dashcam stays on, chances are you’ve wired it up to a live circuit and not a switched live. As long as the dashcam switches off (or loses power) you’ve wired it up correctly.

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