I connected a USB device (which later i figured that it had shortened power lines) to the USB port under the heating controls, and it stopped working 

 

I tried to look at the fuse box, but nothing seems to be burned over there, my next idea is check the transformator which change the 12v to 5v (which hopefully have a replaceable fuse in it) but i have no idea where to look for it, any idea?

 

Thanks.

The circuitry will be fried I'm afraid and it will need replacing, I will be very very surprised if there is an internal fuse in it as most USB supplies and chargers don't have a fuse.

 

If you are lucky it may have just blown a current limiting resistor which acts as a sort of fuse so if your competent with a soldering iron and the surface mount resistor isn't minuscule you may be able to repair it.

any idea how can i get to this circuit? 

It will probably be on a small PCB to which the port is mounted. I'm not familiar with the dashboard on the Octavia so you will have to find a way of removing the trim that the USB is connected to and go from there.

I'm disappointed that it doesn't appear to have some sort of self-resetting short circuit protection, which is quite common on devices like this.

If I am not mistaken? The USB port to which you refer is connected to the "Infotainment" system. Far more likely that all the circuitry for that USB port is contained within that.

Opening up the said system, should it be still under warranty, will invalidate that warranty. Sorry and all that, but hope this helps in some way...........Tony

Have you tried an ordinary USB stick with music on to see if that works.If it's under warranty. You'd be better playing the "I can't get this to work" story. Alternatively find an independent auto or in car electrical specialist. Trying to sort modern car equipment, you could end up with even more damage unless you have the testing tools and skills.

try holding the power button untill the unit does a full reset, this may fix it. it is very unusual for these ccts not to have a current limiting cct to stop any damage.

 

John