Easiest way to get a 12 volt outlet in the back seat?

[philodog]

It is so disappointing that there is no 12V outlet in the back seat. What would be the easiest way to tap into the trucks 12 volt back there? I don't want to run extensions from the outlet up on the dash. The 110 outlet back there is a cheap modified sine wave inverter that will fry any converters.

 

[kapinallinen2]

Installed cigarette lighter outlet and USB outlet into the little cubby hole.
Ran fused 12 volts from the battery, thru firewall and under/next to the center console.