When operating in FM, turn the squelch control fully counterclockwise, then rotate it clockwise to the point where the noise just disappears. Troubleshooting:
Reconnect the vehicle's battery, making sure to connect the negative (black) cable last.
: Not required for the Icom IC-726 or IC-729, which often have these modes built-in. Installation Guide
Comprehensive Installation Guide: Icom UI-7 AM/FM Unit Integration
Disclaimer: This guide is for informational purposes. Working on electronics involves risks; please follow all safety precautions. If you'd like, I can: