- Installation Video: How To Install: ProBEAM Flat Turn Signal Adapter Installation September 15, 2020 13:26 Updated How To Install: ProBEAM Flat Turn Signal Adapter Installation Related articles Troubleshooting: Dynamic Lower Fairing Inserts Troubleshooting Guide - Installation Video: How To Install ProBEAM® 1157 Bullet LED Turn Signals for Harley-Davidson® Motorcycles