Quoted from TheLaw:

All metallicas are actual LED bulbs correct? You need to change the lightbulb.
Now, how many Pinsiders does it take....
I am ASSuming you tested all lights in the menu to confirm they do not work?

Quoted from TheLaw:

What I meant is are they bulb LEDs or boards. If bulbs...
Lift the PF up, jiggle the socket (spider insert) around and see if they work in test after. Look for missing/detached wires.
Just swap a bulb out out of any close socket and see if it works. order new bulbs after
Pop bumper bulb you're going to have to go in from the top, which may be blocked by ramps and god knows what else.

Quoted from TheLaw:

Newer games have printed circuit boards with the leds on them...not bulbs that you can easily change

Quoted from jawjaw:

I don't think MET has any board leds. My MET has a few insert bulbs that like to wiggle loose or have loose connections. You probably just need to push the bulb back in or adjust the bulb wires. If you bend the wires out like a 'V' it helps them make contact better. If none of that works, try to put the bulb into another location and see if the bulbs lights there. If not, the bulb is bad and easy to replace - should be a 2smd cool white wedge bulb. Look up videos on how to raise and lower playfield if you are not familiar with that. It's really easy. Just don't do any work with tools with the power on.
You should be able to access the pop bumber led from removing the cap (top part) of the pop bumper. There should be a couple of visible screws holding the cap on. Same thing, wiggle it around and push the bulb into the socket.