this part was helpful, no diagrams tho if anyone knows of any:
SPECIAL CONSIDERATIONS FOR GROUND-SWITCHED SYSTEMS
Many Japanese vehicles, as well as a few others, use a "ground-switched" headlamp circuit. In these circuits, the headlamp and beam selector switch break or complete the ground side of the headlamp circuit, rather than the feed side. On these systems, it's imperative to use both negative and positive existing headlamp wires to trigger the relays. It is tempting to run the existing headlamp feed wire to relay terminal 86 (trigger feed) and simply find a convenient ground for relay terminal 85 (trigger ground). However, this will not work with ground-switched systems. Run the vehicle's existing feed wire to terminal 86, and run the vehicle's existing ground wire to terminal85.
Now, what are we going to do now that we've used-up our one and only ground wire on the 85 terminal of the low beam relay, but we still have to install the high beam relay? Go to the other side of the car and you have another ground wire! Remember, the relay trigger circuits can be as long as you like, because they take insignificant power. So, you can extend the vehicle's existing headlamp wires to your relay mounting location. It is fine to use this method regardless of whether you have a ground-switched system or not, so go ahead and use it if you're not sure.