Maybe the car got hit by lightning. Seriously, it sounds like a
corroded/loose ground connection at the rear, if it's a lighting problem
back there only. It could also be a MF switch connection problem.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.