I did the XM Commander control unit install in my ash tray. The probem is that whatever contraption that was preventing the ashtray door from falling is gone, and I don't know what it is that's missing.

Can anyone tell me what it is that I need to fix/replace to get the door back in working order?

 

There is a little spring that attaches on the right hand side of the door. It connects to the tray itself. It's a quarky little thing. Look around wherever you were when you took the lid off originally - it'll pop off and try to fly away on you. But it's probably around there if you look.

If you can't find it - i would just swing by a dealership and tell them what you are missing.