The batteries are ok, and when I measure the voltage to the led, it’s 0v. So I think there might be a problem with the switch. I can’t take the led apart on this model, I would have to take apart the whole “plastic tower”, like in this post Uh-Oh, I have my first 2D LED Maglite... FAIL!
I just wanted to know if there were any known problems that I’m missing, or if you have any idea. Thank you!
To find it you'll have to remove the switch/tower thing. Grab the rubber switch cover and pull it out, then there's a hole through the middle of the switch plunger. The LED models technically use a T8 torx screw, but if you don't have one a 2mm hex will usually grab just well enough to get it out.
edit: How are you measuring 'voltage to the LED' without disassembling anything? The only exposed contacts are the tiny little metal squares on two corners of the LED itself - if you are measuring anywhere other than that, you're getting false data.
Yep, I connected the voltimeter to those tiny little contacts and didn’t get any data.
I’m at gf’s house and only have a 2mm hex from leatherman bit kit, but it’s not long enough to get to the screw 
I will try to find the right tool and ask later. Thank you!
Did you scrape off the silicone covering the corners?
You can check the LED by using a 3v CR123 (or 2xAA, though it'd be clumsy unless you have a battery box for them), touch jumper wires to those two corner pads. Remove the D cells first since there's no way to know what position the switch is in.
And how do I know which contact of the led is + and - ? Will it burn if I connect 3V the wrong way?
Sharper pic of the led 
It's a diode - that's its reason for being. It blocks current in one direction and allows it in the other. CR123 or 2xAA won't hurt it.
