Alright, so let me first say that my degree in college was Electrical Engineering. That is why I feel so dumb asking this basic question... But even though i feel like a retard, i'd much rather just swallow my pride and ask the basic question than fumble over it forever! Okay so in our yard, we have a lighting system that is hooked up for a timer. Lights come on at night - go off at day. Pretty standard. I've noticed that like a third of the lights have gone out. So then I went to the transformer box where the timer for the electrical system is. I see that there's one 120VAC line that comes into the box. Then there's 3 12V DC lines that go out (a +/- terminal for each line, for a total of 6 wires). So since about a third of our lights are off, I'm figuring that 1 of those 3 terminals isn't supplying voltage anymore. I went to radioshack to grab a multimeter. I wanted to check the voltage on each of the DC lines. So then I racked my brain back to college... and I remembered that if I want to measure current, I need to break the circuit and reconnect it. And if I want to measure voltage, I should be able to just touch the two leads of the multimeter to the +/- terminal. So I set the multimeter to the VDC setting and I touch the leads to the +/- terminal. I'm expecting it to say something near 12V. Nothing. 0. no volts. Okay weird. I try the next one. Same thing. I try the next one. Same thing. The freaking lights are on right now so I know there can't REALLY be 0 volts on that line. So basically, I have a feeling i'm just forgetting something basic, or missing something... Can some young undergrad who just took basic ECE help me out? I really appreciate it! Want to get these damn lights workin! But in order to fix anything, I need to diagnose the problem first!