PDA

View Full Version : Add switched 12vdc auxillary to Mazda3 for Camera and Tech Devices



zoomister
07-03-2016, 10:54 PM
My 2016 GT has an always-on 12v socket in the armrest. I needed a switched socket for a DOD LS300W DVR. I found a solution that safely supports a socket with no wiring cuts or splices.

Can Tire has a LittleFuse FHM200 Add-A-Circuit device which taps the driver-side fuse block. It replaces an existing fuse with 2 fuses.. 1 for the existing circuit and 1 for the added device. Fuses prevent wiring harness fires and damage to the car switching circuits. Be sure that the sum of the 2 fuses does not exceed the original. For example, if the original is 15amp, then you must use 10+3.5 or 7.5+7.5. In my case, there is nothing loading the second auxiliary fuse so I only needed a single 3.5amp fuse or 10amp max for the DVR.

The 2016 GT has an unused 15amp fuse in the bottom of the fuse-block. The manual says this is an auxilliary circuit and I assume all 2016 builds are the same. The fuse-tap is difficult to plug in because of a plastic section of the block in the way. However, it fits.

Finally, a ground or common connection is needed. I attached a 10amp battery charging clip to an existing ground wire under the dash above the steering column.

http://i886.photobucket.com/albums/ac70/zoomister/fuse_set_zpsecyc3bxs.png (http://s886.photobucket.com/user/zoomister/media/fuse_set_zpsecyc3bxs.png.html)

Hyperion
07-04-2016, 04:11 PM
fyi, i'm pretty sure the fuse holder can go the other way too.

zoomister
07-04-2016, 10:22 PM
fyi, i'm pretty sure the fuse holder can go the other way too.

Wish it did but it is designed to prevent an unfused connection.

The red wire pin is not connected internally to the fuse block so it gets no power if the tap is plugged the other way.