I have a short term subscription for techauthority.com and it may be your best option to buy a subscription yourself. They're running a deal right now where you can buy a three day subscription at the single day price. It'll run you $25 for the three days, it's authentic factory service info, and it covers just about everything for your truck. Just look for the ad in the middle of their main page. You'll have to do the usual setting up an account with a username and password. It's a little more of a pain than it used to be saving information off of it. I used to be able to save some large chunks of info at a time, but now they'll just give you a page or three at a time to convert to PDF. Still, there's a lot of info waiting there. It's not too bad to navigate and they tried to set up the menu the same way they always published paper copies of their shop manuals and it's kinda nice to navigate. I used my subscription to do a reflash on a 2014 long horn today and I'm in an independent shop. My biggest problem is they're stingy with their wiring diagrams. You can print as many as you want, but you can't save them in a common picture format like a jpeg. You do get all your connector and pin out views too though. Overall, it's been fairly handy for the rare occasions I've had to buy a subscription. If you have your own J2534 box for reflashing, it's a huge pain to figure out on your own. I finally got through to somebody in their tech support to help me figure out all the secret handshakes to be flash capable and it's almost a breeze now.

Whatever happens next, I hope it goes well for you. I've just started installing some aftermarket truck accessories for the shop next door to mine and finding that right circuit to tap safely for any occasion is becoming a colossal magic trick. One thing you might want to look for is a delayed accessory power circuit right off your ignition switch since you're just going to tap a relay onto it. If you buy the subscription off techauthority, the wiring diagrams will lead you to an accessory power distribution center under the hood too. It was just a pic of the fuse and relay layout in it without much more detail, but it might be good starting point in your own research too.

 

Thanks for your response. Ive started my project by adding a six-bank of aux switches in the cab. I have a relay controlling power to all accessories triggered by an add-a-circuit on the cigarette lighter (F93). This one is controlled by the computer's power off delay. It seems to work well. I have my CB and onboard air connected to it.

I've had a hell of a time finding room in the cab. I had a 98.5 2500 and you could fit a seventh passenger under and behind the dash. To be honest, the only sizable space that I found was behind the gauge panel but that is not convenient.

This weekend, I'm going to look at running power into the cab. I'm considering under the passenger seat.