Although some would argue that a trailer isolator is not needed, we beg to differ. 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.