I'm just playing around with an Arduino UNO R3 for the first time and I'm already stuck on one of the first tutorials that came with it.
Why would the LED not be working? I've tried different resistors (220, 1k), USB powered or 9V Adapter, changed LEDs etc.
You do know a LED is polarity sensitive? Is it in the right way around?
And second possibility, isn't that one of those breadboards with an annoying break in the bars at the sides. Aka, try to put all connections into the same block (or use a DMM to check continuity over the full length).
Thanks for the advice.
Unfortunately I don't have a DMM around, but after some testing I figured it out. The two jumper wires I used both seem to be broken. I don't know what the odds are since it's a brand new kit and those were the first two wires I picked, but I'm glad it's working now.