Below you’ll find a video that we’ve pulled together showing all the parts and steps required to wire a tablet into your vehicle for either general use or when using one of Workshop 12’s snap-in tablet kits for your car. Overall the process is pretty much the same as wiring any aftermarket stereo into your vehicle with the exception of handling a USB power source. We’ve also previously posted power configuration settings that work best for a tablet in a vehicle to provide instant-on activation of the tablet when the vehicle is turned on, and also allows the tablet go into suspend mode when the vehicle is turned off.
For some people, videos are great, but others would rather have a written article outlining the steps. So we’ve also pulled together all of that information below. To create a wiring harness for your tablet you will need a few parts. Links to specific parts for the 350Z and WRX/STI can be found at the bottom of their respective product pages.
Aftermarket Stereo Wiring Harness
First you will want to pick up an aftermarket stereo wiring harness specific to your model of vehicle. This allows you to plug your new tablet harness directly into the wiring used by your existing OEM or aftermarket stereo. Below is an example of a wiring harness for a Subaru.
The packaging of an aftermarket harness will either have a piece of paper on the inside which will outline all of the wire colors and what they are used for. In the pictures shown, Metra listed all of the colors on the back of the package.
Amplifier to Power Door Speakers
If you were previously using your stereo head unit as the amplifier to power your door speakers you’ll need to pick up a new amplifier to replace that functionality. However, if you were using an external amplifier for your door speakers you can simply run the audio from the tablet directly to your existing amplifier.
For me I was looking for small 2 channel amp that had decent power. This allows me to run the left and right speakers on the 2 channels. If you are looking to configure/tweak all 4 channels of your front and rear speakers separately you will want a 4-channel amplifier.
Voltage Power Adaptor (Step Down)
One of the challenges in adding a tablet to a vehicle is that the USB power source expected by a tablet is 5V DC, but the power supply in a vehicle is 12V DC. This means that you will need to pick up a 12V to 5V DC-DC power adaptor. Luckily these are easy to find and quite inexpensive. There are nice units from Jtron, CPT or others out there. You can even do a search for “Motorcycle USB charging Ports” and you’ll find some that will also work.
Micro-USB OTG Cable (On-the-Go)
The USB port on a tablet is typically used in an either/or scenario. It is either being used to charge the device, OR it is being used to control a USB accessory. The port by default typically doesn’t do both at the same time. Purchasing a USB on-the-go cable will allow you to both charge your tablet and use USB accessories at the same time. Whether or not you require a 90 degree connector or straight connector comes down to available space and will depend on if you’re using the 350Z or WRX/STI plastics. Details on which to choose are found at the bottom of their respective pages.
Standard 3.5mm to Male RCA Cable
To connect your tablet as the audio source for your amplifier, you will require a cable with a 3.5mm male standard headphone jack that splits to a Left/Right RCA cable.
(Optional) 3.5mm Stereo Isolation Transformer
When connecting your tablet’s power source to your vehicle’s electrical system you may encounter ground loop noise that will then travel through the headphone jack, then amplifier and on to your speakers. If this is the case you can simply purchase an inline stereo isolation transformer to clean-up the signal. This transformer simply has a male 3.5mm connector on one end and a female 3.5mm connector on the other which plugs in-line between your tablet’s headphone jack and the 3.5mm headphone to RCA cable going to your amplifier.
Wiring Diagram
All of these parts are then wired together to complete your tablet harness for both power and audio. Below is a schematic representing a generic installation utilising all of the above mentioned parts.
Workshop 12 