My son put a metal marble in my heat vent and it rolls around on corners. i have taken the heat vent covers off and tried a magnet on fishing line ,no luck

This is not an easy process and I highly recommend that you don't do it. Try to use a flexible magnet to get behind the panel and fish out the coin or at least move it so it doens't make a sound.

It's highly unlikely to cause any annoyance.. is it a modern plastic pen? If so, then it is weaker than the high tensile steel cable that has to move to operate the handbrake.
If it is a plastic it will lubricate any metal it rubs against..
If it is metal use a magnet and go 'fishing'...

Doors also can be jammed by objects that have been placed on the dash and have disappeared down the defroster ducts. The cure here is to extract the object from the plenum by fishing through the heater outlet with a coat hanger or magnet - or removing the plenum
God bless you

You could buy a tool that has a magnet to pick up small metal pieces. You can find this tool at a store that sells tools and you should be able to find it in some auto parts stores. This tool is kind of like an antenna that you pull out of a radio and it has a magnet at the tip, or some of them have a flexible rod with a magnet at the tip. Then you could slowly insert it into the vent and move it very slowly so you can hear if the magnet catches it (it must be quiet). Just slowly feel around with it and make slooow movements. Just fish around at different directions and angles and you may have a chance to pull it out with a magnet.

you can try a skinny magnet and try getting at it threw the vent it's most likely a ink pin, if that does not help try removing the center vent or the driver vent it just snaps out and try to get at it with a magnet, if you can't get it with a magnet you will need a three finger grappling tool to try to grab a hold of it otherwise you will have to remove the center air conditioner duct which is not to hard.

You have to pull out the dash and ac ducts, depending on which vent it went down will depend on how hard it will be to get it out, you could also pop off the vent cover and try to fish it out with a magnet, but thats the only way i can think of, Good luck, Please rate me.

marble in the air vent seen this before

sounds like a bolt may have come off or something, check to see if there are any recalls due to steering columns

try a fish it out use a magnet and some string

In left rear wheel well under a plastic cover is your fill and vent pipe
A coupling from plastic pipe to metal pipe must be taken apart and air blown into tank
This plastic line is bent down and collects overfill and moisture, thus not allowing tank to to vent as you fill.
Once you have cleared plastic line and reassembled coupling , gently bend metal pipe so plastic line drains towards tank.
Manufactures fopa