When I told my boss he was really quick in response without needing anymore information haha... He said it's most certainly one of the two major connectors have the wires loose. He said it's either inside the edison plug that one of the cords came loose or the start of the cord into the light has come loose.
The edison plugs coming loose is pretty common and easy to fix. If you've ever worked with speaker wiring you'll be able to fix it pretty easy. Take off the edison plug, notice which wire goes to which part of the plug. Then strip them each down a quarter inch, cut off the fiberwire around the wires, and insert the fresh wire section back into the edison. Done.
If that doesn't work then your problem is the start of the cord. You'll have to do the same thing here except you'll need to actually take the Arri's light casing off so you can get into the light socket section itself where the cord plugs in. Do the same thing with this end of the cord. (Yea you've lost an inch or so). This problem by the way is mainly only caused when the light isn't correctly strain relieved when you're using it.
You can try to do one of these two fixes, my boss is pretty sure it'll fix the problem. Or you can bring it to one of our many Central Florida lighting houses (Like Murphy Lighting) and for a fee they can fix the light for you. Downside is that they charge a lot, you'd be looking at least $100 to get it fixed, however if it breaks again in the future you can be like "Hey so you fixed this, and it wasn't fixed. Try again?"
Hope this helps.