Welcome to the Forum 
This may help Power Key Rebuild TIPS
Left Click on anything I have underlined as they are links to interesting information.....usually.....
I would remove the Switch as described in the link above and work on the Key Removal on the bench AND recondition the Switch as
Kevin described in the above link.
I have reconditioned four Full Power Switches exactly as
Kevin described and they all work perfectly.
When Full Power Key is ON.....the Panel on the 1990 above Bose Radio will show FULL ENGINE POWER as shown by a photo provided by
bamawrx.
On the 1991 there is a small green light to right and above Full Power Switch that lights up when Full Power Switch is turned on.
On the 1991 The Panel as shown below will be blank when the Full Power Switch is turned on unless there are error codes present.
