CDR-210 to CDR-220

[elav]

OK, so I figured out that I simply need to remove the CDR-210 cage to get the CDR-220 radio to fit (simply slides in once the cage is removed). I'm now working through two additional issues:

1. SOLVED: I previously entered the incorrect radio code too many times and the radio now displays "WAIT". I've read that leaving it on for 30 minutes resets this but this didn't work in my case. Anyone know how long it takes to reset the radio? Update - I let the car sit for an hour and then let the car idle again for 15 minutes and it reset. I was able to enter in the code and get it working!
2. The CDR-210 has a ground lead on the cage. I disconnected this wire and grounded it (to the large brown wire in the radio harness). My car now honks once when I lock the doors. All the trunks, center console, etc. are shut so I've got to imagine that it is the change in radios. So I'm suppose to run that wire from the cage to ground, right?