Make Sure It isn't the Runway You Are Looking At...
Be sure the line you are seeing isn't the synthetic vision display of your airport's runway, Can you post a screenshot for us? Is the line present when you display other screen pages such as EMS or MAP? It's very easy to misinterpret the black line you are seeing on the PFD display when it is simply the runway.
Bob Walden (Waldo), CFII-ASMEL
KFFC "Falcon RV Squadron" Peachtree City, GA
RV-7A Tip-Up, IO-390, 450+ Hours
RV-12 (Sold)... RV-12 Transition Training
EAA/AOPA/Vans Air Force 2018 Supporter