Headlight wiring harness with relays

After reading horror stories about the headlight/wiper combo switch melting due to the full amperage of the headlight beams going through the switch, I decided to install a wiring harness with a set of relays.  MSA sells a great plug-and-play unit which is built by an avid Datsun Electrician, although I decided to save some money and build my own.  At the end, I invested about $40 and have much better low and high beam headlights, and will save the combo switch.

I started off with a cheapo pre-made relay wiring harness which I acquired from Amazon for pretty cheap (Amico Car 30A Fuse 2 H4 HID Headlight) and a set of harness plugs and some wire/shrink wrap.

 

I next needed to extend the wiring harness and include the correct harness plugs to allow me to plug directly into the Datsun wiring harness as a feeder and then into the headlights directly.

 

Then it was as simple as unplugging the existing headlights and plugging in my new harness, including connecting it to the battery to power the relays.

As reference, here's the best diagram/explanation I can find.  Thanks go out to the original author.