TLDR: OEM style switch wiring -> Yellow harness wire to Green switch wire. Red harness wire to Red1 switch wire. Black harness wire to black switch wire. (Red2 unused). Yellow on the harness is always hot, red is the trigger wire, and black is ground.

Switch Update:
I had a spare switch from another project I didn't use yet so I decided to try wiring it up. Most aftermarket OEM style switches use the same connector with different wire colors. I'll reference the colors in the diagram below but similar switches should have the same wire functions (my switch wire colors were actually different but the wires correspond to the same location on the connector).
The Lasfit harness has three wires that come into the dash area (Yellow, Red, and Black). The Yellow wire is constant power from the battery (always hot). The Red wire is the trigger wire that goes into the relay to trigger the lights to come on. The Black wire is the ground (pretty standard). I confirmed the Yellow power wire with a multimeter but you can also see it connecting with the wire from the battery at the base of the relay (see photo below). Once you know this and understand how the OEM style switches are wired, it should be fairly simple (let me know if I should do a separate post on OEM style switch wiring).

Here is how I connected the switch:

Yellow from the Lasfit harness to Green on with switch (first wire)
Red from the Lasfit harness to Red1 on the switch (second wire)
Black from the Lasfit harness to Black on the switch (fourth wire)
I did not use the Red2 wire on the switch (third wire) but it can be combined with the Red1 wire (second wire) to illuminate the entire switch when the ditch lights are on

These connections allow the switch to illuminate when the ditch lights are on and it is not illuminated when the ditch lights are off. I am more confident that this setup will not drain the battery, but make sure you don't leave them on when the vehicle is off (the ditch lights can be used even if the vehicle is off if using this wiring).
Hopefully this helps those with similar concerns. Here is the diagram and a photo of the relay wiring:

Typical OEM style switch wiring diagram (most aftermarket switches are the same with different color wires):


Here is a picture of the relay. I colored the section running to the interior in purple (this is the three wires, yellow, red, and black). The green arrow shows the red trigger wire going into the relay. The blue arrow shows the yellow power wire combining with the wire from the battery at the base of the relay.