Uninstall icon?

PLug in your 350 USB cable to the computer, Click on the drive letter that is associated with your GPS, and open the Garmin file. You will see the vehicle folder that contains the icons.
Erase what you don't want. Maybe you should save it somewhere first.

That is a good idea...even better would be to save a back up of the entire contents of your GPSr on your computer somewhere, including hidden/system files.

However, if you need them again, you can always download them again from the webupdater. But backing up anything before you do anything (not just GPSrs) is a great idea.

Please don't delete your current vehicle. If you do your Nuvi will crash during boot. You will need to copy the file back to allow your Nuvi to boot again. I learned all this from experience and if I did not have my backup I would have a Nuvi brick.. or at least a very uncomfortable conversion with Garmin support.

Many of us, including myself have deleted vehicles without issues. I only have the blue diamond that I use, the rest are gone.

I deleted the extra vehicle icons and had no problem with my Garmin. Thanks for your help.

With no problem.
I just wish there was some way to make the blue triangle a bit smaller.
Could it be brought into paint or some such program and made smaller?

that is the current use on your garmin display. You can delete all vehicles you wanted to but make sure the current one that on display don't get deleted.

Right.

The first thing I did was to get the things I wanted to detele backed up and then deleted vehicles, demo books, demo mp3s, unwanted voices, etc. Ball park deleted -- freed about 500MB.
It is a good space to be used for POIs, isn't it?

Yes, that will serve you for a long time. POIs don't take that much room.