Why have the lights on my 2000 Club Car DS stopped working

If you have 12V bulbs in that unit, then 8V is too low. Need to chase the voltage back to see where it's dropping with a multimeter. Might want to start off at the on/off switch. If you have LED's then possible LED driver has failed.

Thank you for trying to help. Not LED's. Could it be the voltage reducer? When I put the volt meter on it in the continuity position I get nothing, when I put it in the curly horseshoe (ohms?) I get a reading of about 16.

Is the voltage being produced by the voltage reducer, responsible for delivering the proper voltage to your lighting system? If it is, then you need to take voltage measurements on it's output to determine if the voltage level is correct. Not sure why you are doing continuity checks at this point. Doing a continuity check is just making sure that a component is continuous, that is no breaks along the way of say a wire. The ohmmeter section of your multimeter is using the same principle to measure the resistance of a component. The two extreme examples of this would be reading 0 ohms on the resistance scale of your multimeter(or on the continuity tester a audible beep signifying the meter was reading less than 200 ohms) which could indicate a "short circuit" and the other would be no change in the display on your multimeter signifying that continuity is broken (in other words a broken wire or connection etc). Your reading of "16" is meaningless unless you stipulate what scale setting you have your multimeter set on; it could be 16 ohms, 16K (thousand), 16M (mega) etc. In a nut shell, the continuity setting is just verifying that, yes there is continuous access from point A to Point B so therefore no breaks in the component or wire.

BTW, just to somewhat clarify the term "short circuit". Some short circuit occur when a low resistance is presented between the voltage supply and the ground. Extreme example would be a "dead short" if one took a cable and directly hooked it across the two terminals of a car battery (Do NOT try this!). Shorts can also be produced when electonic components are inadvertently soldered together at the wrong points (which is called bridging). Most people use the term "short" without really understanding what the term means. It doesn't mean a wire is broken but a broken wire can cause a short circuit because it is loose and and the uninsolated end of the wire touches the wrong place electrically. An "open" component, as stated before, is where there is an actual break in the wire or component. The two terms not not interchangeable. A good example of this is a glass fuse found in a lot of electronic equipment. With respect to itself, when an ohmeter (or continuity) leads are placed at each end of the fuse, a really low resistence is displayed. When the same action is done on a fuse that has "blown" due to to much current being drawn (as in the case of a short circuit), the multimeter display will not change or to put it another way, it is reading a resistance value of infinity and therefore classified as an "open circuit"

@propman I replaced the voltage reducer and I now have working lights, Can't thank you enough.