The Guardian case in which you're talking about has the three red led lines on the front of the door. I actually had the same problem with my lights not working so I took the door off. It is actually only one very small led that lights up a clear plastic. This is powered by molex... Not the motherboard. The lights in question are not indicators of any sort, merely cosmetic.
If you have any soldering skills you could simply solder on a new led. Would be cheap. Though I'm trying to find out if I can't just find that exact cable in order to replace it.
Also, taking the door off is a simple break down including a couple screws and two cotter pins.