I did the 4 beam high beam mod on mine (99 Tahoe) and it works great. I used a factory underdash brake controller harness for a 99+ truck, took it apart and inserted the wires into a blank relay spot in my fuse box. Added on fuse holder and tied the wires into the headlight harness right next to the fuse box. Looks COMPLETELY factory, uses a factory relay and works great. It took a little work getting into the fuse box, and a little planning to get everything right the first try. I can't be happier.