Last night when I switch off the ignition in my 300d the radio decided to stay on. Had to pull the fuse under the hood to make it go off. The day before I was walking past the trunk and I saw the antenae go up about 7 or 8 inches and then retract. I hadn't been in the car all day. Radio and antenae have been working flawlessly up to this point. ideas?

My best guess is -believe it or not - your battery is dying. I remember when my battery was dying the climate control would come on by itself, the radio would come on by itself and a few other weird things happened. Test the battery if it is old to see if it charges.

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles