What fuses did you check? There are two (2) fuse boxes: one under the driver side footwell and there is also the fuse box (IPDM E/R) under the hood next to the battery.

 

 

Code U1000 refers to a problem in the CAN circuit. In this case specifically with the AV not transmitting/receiving signals. Determining what short circuited and where is virtually impossible to do here. Best advice would be to check the FSM as there are several self-tests and flow charts you can utilize to help narrow down what might need to be repaired or replaced.
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It could be as simple as replacing the Radio/HVAC switch panel or it could be a more serious problem with the AV headunit.

Good luck!

 

just wondering how bad of an arc was this? usually a small arc from shorting power to ground can be tolerated and at most a fuse in the fuse box would blow if it was close enough to a component that you tapped power from. if there was a prolonged and large enough arc you may have burnt out the component itself. sometimes components such as the radio or sound amp has another fuse located on the back or inside the unit itself (depending on the make and car manufacturer). without looking and tearing stuff apart it will be difficult to diagnose here in the forum.