What is wrong if the engine dies when you turn on the lights?

If the engine dies when you turn on the lights, it could indicate a problem with the electrical system, such as a failing alternator or a weak battery that cannot handle the additional load. It may also suggest issues with the wiring or connections, leading to a short circuit. In some cases, it could be related to a fuel system problem that coincidentally manifests when the electrical load increases. A thorough diagnostic check is necessary to pinpoint the exact cause.