Originally Posted by Hulk
..The one that Nakman posted will probably run a blow dryer.
Yeah it will, with the truck running.
If you're expanding into 12v then you should set up a separate fuse block like Romer describes, so you can leave behind the cigarette adapters. I'm sure we can suggest wire gauge and fuses to make it safe if needed... I have mine right below the passenger seat, accessed from outside the truck. The lead comes through the grommet in the firewall and under the plastic door sill, I drilled a hole under the seat and ran the ground through it to the frame. Now I have almost unlimited terminals for new stuff, and never have to mess with the firewall grommet again... in fact don't even need to open the hood to add stuff. Mine currently runs my fridge, second 12v plug, rear seat heaters, brake controller, and reverse light.