To me it sounds like there might be a short somewhere. You should replace the fuse and then turn the vehicle on. If there is a short it should blow the fuse right away and a trip to the dealer service center for warranty work will be in your future. It is also possible that something that was previously plugged into the 7 pin caused the fuse to blow.

@Huc Side note for you. Your karavan does not have power pin of the 7 pin connector actually hooked up to anything. I was digging around in some of the 7 pin wiring the other day and found that the wire is just cut and loose in the bundle of wires shrinked wrapped under the tongue box. In my case I repurposed it to power my backup camera on the trailer. This way the camera isn't always drawing power from the main battery.

 

Yah that's what I believe K.K. USA mentioned during trailer hand off and pre-order. Which makes perfect sense as the LRD plug would have power but the KK cable doesn't 'need it' as there's an Anderson plug

Thanks for clarification and great tip of the camera option - might be something to add!

 

The wiring diagram is interesting as it shows the 4 pin flat connector and 7 pin round one on the same diagram. Took me a sec to figure out. Love learning new things / deciphering.