Tekosha ZCI ModuLite connects straight to the tow vehicle battery. As a result, it isolates the trailer light operation from the tow vehicle electrical system. Both interior and exterior mountings are possible, thanks to the ZCI's sturdy design. The installation process is easy â any cutting or splicing of vehicle wires is not required. Please, keep in mind that Tekosha ZCI ModuLite is compatible with vehicles with 12 volt system only.