This is a mod originally created by and uploaded with permission from User-Domain-Error. She no longer hosts files herself, but allowed me to share this one here. I have repacked it into .mods.

Requirements:
DLC with robodog installed.
If you don't own the CE, you can edit the dog in using Gibbed save game editor.
In gibbed load your latest save and then go to 'Plot' > Enter 21187 in the 'Bool' box > Get > check Is Set > Set (window should read bool 21187 is set to True). Save your game.
Open your game and load the save you just altered and you now have the RoboDog (via Mwraight2013).

ME3Explorer. You can download ME3Explorer here.
For the most current revision (recommended) you'll need the SVN: How to use the SVN version

Instructions:
1. Install the .mods with Mod Maker in ME3Explorer

2. Update the DLC TOCBin
Developer Tools->TOC->DLC TOCbin Updater
The file you want to update is located by default:
"C:/Program Files (x86)/Origin Games/Mass Effect 3/BIOGame/DLC/DLC_EXP_Pack001/CookedPCConsole/Default.sfar"

Directions are also included in the download. There are 3 color options: white, red, and brown with blue stripes.

Common Troubleshooting:
If you are modifying DLC you will also need the DLC patcher HERE to bypass the online check.
Install the two dll files in Origin Games/Mass Effect 3/Binaries/Win32

If it is your first time using ME3Explorer or updating since DLC modding changed to unpack the sfars, you'll first need to do a new treescan including all the DLC. More info on the official forums.

Useful Links:

ME3 Explorer First Time Set-up