Either go to a junk yard and cut off the correct connectors so you can solder them onto the new running board wiring or just cut the old connectors off and do the same on the truck side. You have to solder them or the splice will corrode under there. Heat shrink over the solder joints. There's also self sealing solder type connections like in the link below. Make sure there's no green crustys in the copper wire or the solder won't take.
Finding the correct Toyota connector would probably be tough.
https://www.amazon.com/Connectors-Ha...s%2C208&sr=8-5