Accessory Power 2001 Ford F-350

One or the other off of the factory radio would probably be fine but you may be pushing it with both. I would just go right to the ignition harness pulling those 4 push clips and dropping the underdash panel couldn't be easier..You'll see the ignition harness to the right and a bit behind the fuse box. You can remove the 4 10mm bolts holding the fuse box in and pull it out a little to get more room if need be. (Although definately not necessary if your just tapping into 1 wire..) You should always test your wires first, but you should be fine using the gray / YELLOW or BLACK/ green wires @ the ignition harness for accessory power.

Great. Thanks for the information, I would prefer to use accessory power from the ingnition system anyway. Just curious, how do you know which of the wries in the igniton harness are for what function?... diagrams/charts, and if so where can I get some?

"Just curious, how do you know which of the wries in the igniton harness are for what function?" You just kinda know after doing remote starts/alarms/etc on the same cars all the time. If not you can just use a test light or multimeter to test the functions. (Test lights not usually recommended but you'll be fine testing the thick ignition switch wires..) Basically I can tell you a bunch of the wires you'll see in there: Any thick yellows or GREEN/ violets should be 12v+ constant power. Put your test light on these wires and it should light up all the time. With the car off, and with the key cylinder in all positions. Your starter wire will be a RED / light blue or a dark green wire. This wire will light the test light ONLY when you turn the key to the crank position and go out once the car is started. Ignition will be a RED / black wire. This wire will light the test light in ignition, accessory, and run positions. It will stay on through the crank cycle. Accessory will be gray / YELLOW, RED / black (there's two - one is ignition mentioned earlier.), and black green. These wires will test same as the ignition wire except they will drop out quick while the truck is cranking and come back on once it's running. Hope that helps..They change the colors for those trucks so often hard to say exactly which ones you will have but they should be pretty close to that above. Good luck, Mike