Thank you for your prompt reply. I used a 1k resistor and got the circuit working. Now I'm worried that, since this is part of my permanent test rig, in the event that we need to test a unit at a higher voltage (up to 48 volts) that it will burn my LED out. I am thinking that I need to use relays to circumvent this possibility. I know the basics of relays but I have no clue how to implement one in this situation. The only relays I have found in our bins have the following info on them:
0.6A 125V AC
0.6A 110V DC
2A 30V DC
Would these be ideal for such an application? If not, what should I look for?
I apologize for all of the ignorant questions but I have always been a software engineer and I am quite new to electronics beyond simple repairs.