There are a variety of underhood and underdash sources from where you can get 12 volt key-on power. However, I would suggest that you use these to power a relay coil only. Then you can run a wire from your battery, through a fuse to the relay contact, and have the relay pass power to a fuse block of your own installation, from which you can then tap whatever future mods you wish. You can use the green wire with red stripe (IIRC) under hood, which goes to many things including the cruise control, glow plug controller, IP and alternator. I think there is also a test plug that may be part of the automatic trans or emissions test port that is part of the wiring harness tucked up under the drivers side fender area that has this wire.
