My installer has connected the parking brake wire to the parking brake. I would like to leave this connection intact and just add a switch. I am versed in car wiring so from reading the threads, I believe I can do the following.

1. remove the mute wire and place in slot above

2. connect mute wire to ground using a tap

3. connect another tap from ground wire to side a of switch

4. connect side b of switch to tap on parking brake wire.

would this work? I should then be able to leave the switch "grounded" and "unground" as needed.

That will work... but why do you need to do it that way? Unnecessary switches are a pain in the ass. Why do you need to leave the parking brake switch hooked up? Just ground the wire and be done with it.