I have a lot of electrical add-ons, and have more planned in the future. I want everything to be as factory as possible - even down to the wiring under the dash.

Instead of tying on to an existing random power wire or running a new wire from the battery for any of these projects, I want to utilize the factory harness as much as possible. There are 15 unused fuse spaces in the power distribution box under the hood. Some are for options not on a Lightning (like Supercrew rear power window fuse), but most are just not used at all.

When I look at those fuse spaces, there is a power wire running from the battery, but no second wire leaving the box running to the rest of the truck.

I want to carry the wiring on from that point.

So what would I need? It looks like I would need:
spade or female terminal end (depend on the style fuse space) to go in the
box
wire to go from distribution box to the firewall harness plug
terminal end to go in the plug on the engine bay side
terminal end to go in the plug on the cab side
wire to either run to the accessory

I would get different colored wiring for each wire ran, and could leave them all coiled up and zip tied under the dash, leaving the fuses out (so the wires would not be live). Once I had a need for a power wire, I could run a wire to the option and plug in the appropriate fuse. I could also then jot down the accessory in my owner's manual next to the 'Not Used'.

Off the top of my head, these are the things I either have or plan to have soon that could be wired from this:
Heated seats -
There's a fuse space in the dist box for heated seats, but only wire run to
one side of the fuse. Thinking about this option is what gave me the idea.
Power folding mirrors
Interceptor gauges
Power tailgate
Power Tonneau
Air Compressor for air bags
Flip Plate
Rear Camera (not sure if it'll need it's own power)
Bed lighting
Dual air pressure gauge for air bags
Navigation system (might need an extra power wire)
Power inverter
And I'm sure a dozen other things I'll think of to add.

I guess I'm wondering if anyone has tried this before.

Any input is appreciated. I'll probably get started on it before the end of the month.

Thanks,
William

 

It would REALLY help to know what YEAR your truck is... More info is better - is it a Lightning? A full list of options & current mods in your signature would eliminate confusion later.

In the meantime, read these captions:

 

Sorry - Mine is a '03 Lightning. The only options for Lightnings were tonneau covers and bedrugs, so electrically they are all the same from the factory.

Thanks for that link - it's nice to see what the fuse block looks like torn apart BEFORE mine gets opened up.

 

Something you SHOULD keep in mind too, if you do this, is to document your changes to the fuse box as an addendum to your owner's manual so you won't have trouble figuring out the wiring later on.

And, if you sell your truck, the new owner would be grateful too.

- Jack

 

I definitely will.