Review on H4 Headlight Relay Harness Kit for Toyota Pickup & Tacoma - Solve Dual Ground Problem by Jerry Frey

I was able to install this new LED Headlight Wiring Harness in about 15 minutes. The new headlights required dual hot/single ground, the opposite of Toyota's setup. I used the passenger side light to connect the wire harness as it is closest to the battery and you need to connect the positive wire to the battery. I routed the wiring harness for another light between the radiator and the radiator grille. Two screws in the case to attach (and ground) the relay and you're done. All plugs and cables are already connected, so all you have to do is connect them to your new headlights. The high/low switch now works properly and the new LEDs are incredibly bright. Very important.