if the dealership cant help fix this problem, then find a different repair shop to take a look. Check yelp, google reviews, ask friends, etc.
Check around for a high rated auto shop in your area and ask if they have someone well versed in auto electrics. My dad was excellent in auto electronics (he’s retired now,) but it has always been a struggle for me. Not all techs are as competent in all areas.
You are not obligated to go to the dealership, and quite frankly, will often get better and cheaper service from a non-dealership repair facility.