Can I add LEDs to small electronics when they originally had none?

[jpro]

I would like to add an LED to a portable CD player that comes on when the CD player is running. The lid of the player activates a switch that lets the player know the lid is closed and that playing can begin. I would like the light to come on when the lid is closed. My problem is that up until this point I have only worked with LEDs in a very straightforward way, directly hooking them to a power source and basically following instructions to have them light up with a switch etc... (think along the lines of arduino basics).

Now I am a bit confused if this will work with all of this other "stuff" in the way (the CD player board and all the components). The CD player runs on 4.5v DC. Is it possible to hook up an LED somewhere around the lid switch? Is the voltage too low for it to even work correctly? Would I risk damaging the other components on the board?

Thanks to anyone with some help. I am still new to this so if I left out any important info let me know and I will try to supply it.

 

[(*steve*)]

It's possible, but you'll need to determine how the switch is connected. Most likely it connects to *v or ground, and if so, there is little preventing you adding a LED and an appropriate resistor.

 

[jpro]

It's possible, but you'll need to determine how the switch is connected. Most likely it connects to *v or ground, and if so, there is little preventing you adding a LED and an appropriate resistor.

Do I need a multimeter to figure out how the switch is connected? The switch is soldered at two points on the board. Is it correct to think that if the switch is connected in the correct way that The led would need to be wired in somewhere after the voltage continues through the switch?

Say I find that the switch is good to add an LED. Could I remove the switch from the board, wire the first pin on the switch to the corresponding place on the board, then wire the correct resistor to the other pin, then the LED, and then back to the second corresponding place on the board the switch was connected to? Will the resistor affect the voltage such that I will need to add something again after the LED to correct the voltage?

Maybe I am thinking about this wrong. I guess what I am not sure about it what extra I will need to wire in so the LED will not affect the performance of the CD player.

My goal is to have a nice blue glow coming through the window in the lid of the player while a CD is playing without having to add an extra power source.