The NAMZ Trailer Isolator takes power directly from the battery and grabs the signal from from your brakes, running light and both turn signals. This process sends those signals through a bank of 4 relays before it sends it off to the trailer. The relays draw power from the battery and not your OEM turn signal module, thus preventing premature module failure. A factory turn signal module is a few hundred dollars making our isolators a worth while investment.