LED wiring questions?

[Batteau62]

Let me say, I am an electrical noob, but willing to learn.
I have two questions:
1.-In the RepRap wiki, in the "MAX mods" at the bottom of the page. It talks about wiring an led to the limit switch. Do I need to add a wire to the harness for the +? But it also talks about not using the + on the Rambo board or bad things will happen? The pdf diagram shows an additional + wire. And I can add the 150ohm resistor. Can someone do a little clarification of this mod(with pics if possible please). I like the idea of a visual cue when a circuit is tripped.

2.-I have a bunch of these:

cartridge led lamps-5v 20ma

my idea is to drill a mounting hole in the top plate and solder jumpers to the bed like normal and run them to one of these indicator lamps. Should I still put the resistor in the circuit? I'm not sure if these have one built in? my instinct says I should include the resistor.
I like the idea of being able to change the led color if I choose, or it blows etc.
Thanks in advance!

[Eaglezsoar]

A datasheet for the Led cartridges you have is at http://www.dialight.com/Product/Details ... 573333500F
The resistor seems to be integral to the cartridge and they are designed to operate at 5 Volts.

If you look at the Rambo schematic the third "+" wire is connected to VCC which on the Rambo is 5 volts. I think they
include the warning about using that VCC connection because a short to ground on that pin would destroy the 5 volt
supply circuitry on the Rambo. You can get 5 volts from the power supply if you are using the original power supply
just use the red wires.