So I have a 2014 fx4 ecoboost. I'm wanting to tap into several spots in my passenger side fuse panel using those add-a-fuse adapters. I've used my multimeter to find ones that are always hot or hot when key turned on. The question I have is my #10 fuse (10A) according to my owners manual says it is the Run/accessory relay. Wouldn't that be a circuit that should only be powered if the key is in the run position or vehicle is running?? Cause right now I get power to it all the time with no key in. My other question is #43 (10A), #44 (10A), and #45 (5A) fuses are Not Used (Spare) according to the owners manual. When checked I get no power to them at all, keyed or not keyed. Can anyone explain why that might be? I checked the fuses and they are good.

 

https://www.startmycar.com/ford/f-150/info/fusebox/2014

I could be wrong, but I think you need a matching fuse and/or relay in one of the spare engine compartment slots to use a spare in the passenger location?

I was planning on using one of those piggy back add a fuse wires in the spring for a usb charger with voltmeter. I was going to use the heated rear seats passenger fuse location as I don't have heated rear seats and there's a fuse for it in my passenger compartment fuse box as well as the engine compartment fuse box.

 

I wanted to use that same fuse as well but it is too close to the #49 Relay and the Add-A-Fuse won't fit in that slot. I would have to flip the Add-a-Fuse around and technically it would be inserted the wrong way. One of the fuses I plan on using is the #38 (Delayed accessory - 110-volt power point, Radio) circuit. It only powers up when the key is in. I'm in need of 3 circuits that only have power when the key is in and 1 when the lights are on which I found #30 (Front parking lamps) that I will be using. I just wish I knew why those other three that I mentioned above aren't working at all.

 

really good that you know this, many don't, and it's very important the the add-a-fuse be orientated correctly.

 

So back to my original questions. Why is the #10 Fuse (Run/Accessory Relay) getting constant power? Shouldn't it only be getting power when the key is turned to the run position? Also, Why would fuses #43, #44, #45 (Spare Not Used) not have any power what so ever? Does anyone else have this problem?

On a side note, does anyone know how to get a wiring diagram for my vehicle type. More specifically the Wiring around the Passenger Side Fuse panel. There are numerous other wiring connections attached to the fuse panel that I'm curious what they go too. I noticed on my vehicle that at some point a couple wires were tapped into from just above the fuse panel that are feeding back to the rear of my truck. I think they are feeding back to my locking tailgate if memory servers me right. This was done by the dealership as an option they did when I bought the truck. If I could know what some of these other wires are then I could just tap into them instead of using an Add-a-Fuse adapter.

 

At the risk of stating the obvious ...

WAD (Working As Designed) - power-points for when the key is not turned-on.

WAD (Working As Documented) - Not used so (probably) not wired.
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