FS 2002 0nly.
If you have downloaded the latest Cessna 152 from here...>>>
http://www.simviation.com/fs2002props61.htm
...you will find that the radio doesn't work.
The designer has omitted to include the "Avionics Switch
gauge" on the panel.. :'(...!
I've ferreted around and found a default gauge which works... ;D...!
So, in the Panel text File, add this entry...>>>
gauge37=Cessna!Avionics Switch, 317,550,22
...and SAVE...

It will insert the switch between the Strobe switch and the Beacon Switch...

(This spot is presently "blank").
Have fun with the latest '152...

Cheers all...

Paul.