Here's how "Route Magnet" works. When you enter a destination into the nav system, based on the preferences you have specified (shortest route, fastest route, avoid tolls, etc...) the computer will plot a course to get you from point A to point B. Now let's say that you want to go an alternative way to reach your destination. What you can do with route magnet is, using a cursor of sorts, you point the system to an area that you would prefer to be routed through and the nav system will recalculate the route to take you past that point.

What's nice too, is that the system seems to store the last route magnet you set, so when you go back and select that destination again it will ask you if you want to use the route magnet that was previously stored.

I don't use the feature a lot, but it's nice to have on occasion.

Note that I believe this feature is only available on MkIV's that are not in "U.S." mode (i.e. after you do the downgrade/upgrade trick to eliminate the accept screen)