I want to find a way to make the light work like a glove compartment: Open on, closed off. Anyone done this?
Looks good! I thought about the hinge on/off as well but could not find a nice switch that the buyer I did it for could easily install. There are a ton on EBay though and I am sure would work fine if you don't mind a little extra effort.
I think the best option due to the space you have to work with would be a miniature reed switch that is commonly used in model trains and alarm systems that actuate with a magnet. You would need to find one that is "normally closed" instead of "normally open". "Normally" in switches means that without being activated, the switch is in that state, you want one that when the magnet is NOT near the switch it IS allowing power. Mount the magnet on the door of the ashtray, so that it opens the connection when the door is closed and closes or allow power when the door is open. When the door opens, the magnet causes the switch to close and activates the LED lights. If you cannot find a normally closed switch there is a way to make a normally open one act like an closed by using another magnet. Going this route you would only need to attach a magnet and route the wiring.
Or, you could make some mounts near the base of the ashtray and use a small micro push switch, something like a pin switch for car doors and hoods. Space is limited but it should work with the right mount.