HOWTO: Wire a Laptop Hard Drive to your USB compatible Car Stereo Head Unit

Things you’ll need:

Laptop Hard Drive - http://www.newegg.com/Product/Product.aspx?Item=N82E16822136391
External USB case, with USB-Y cable - http://www.newegg.com/Product/Product.aspx?Item=N82E16817392032
DC USB power source - http://www.amazon.com/Powerjolt-Dual-Universal-USB-Charger/dp/B001Q2FM5E/ref=pd_cp_e_1
Switched 12V Power Source – I spliced into my head units power source.
Cigarette Lighter Socket - http://www.amazon.com/Parts-Express-Cigarette-Lighter-Socket/dp/B0006TIRZA
Head Unit that supports USB playback, not just iPod. - http://tinyurl.com/yf2mnoh

Find your Switched 12v Power Source (switched because you won’t want your hard drive constantly spinning, even when the car is not running). Splice into it and add the Cigarette Lighter socket. I added mine in the dash behind the radio. You’ll want to use mid line wire tap.

Plug in the DC USB Power source and then grab the USB-Y cable from the External Hard Drive case and plug in cable 3. (See diagram) You might want to add a USB extension cable if you plan to house the Hard Drive in the glove compartment.

Now plug in cable 2 to the External Hard Drive case. The last end of the USB-Y cable will plug into the Stereo Head Unit.

You’ll want to format the entire drive as FAT. If you’re using a PC for this, use FAT32Format.exe (Google).

Add as much music as you want and you’re set!

There might be an easier way to get power to the hard drive but this seemed like the easiest, fastest way to accomplish this.