My husband is no professional, but these are his thoughts.
You need to check if there is an inline fuse in the wiring harness somewhere around the headlight wiring or battery.
Our dodge truck has that type of set-up and that fuse blew one time leaving us with no headlights.
Pull each fuse at a time, example headlight fuse.
Get your power tester and touch it to the metal where the fuse was. This will tell you if you are getting power to the fuse box.
When it comes to electrical stuff, you may want to take it to your dealer and have them check it on their computer.
Good luck. Hope this helps, keep us posted.