Yep,
I used a Belkin 782-2226 HHH Accessory "Add-A-Line" for mini fuses to do the tap. Look in your service manual for a switched fuse location in the fuse panel. I think (?) I used #16, but check that as a switched line.
Actually I ran the whole Painless wiring through the firewall as I use it for in cab accessories, or switches to controll other accessories.
Bob Weis