“Not Used” and “Not Used (spare) (Raptor)” Fuse Locations

The attached pic shows the fuse block diagram from the owners manual for a 2019 F-150. I have highlighted in yellow locations that are labeled in the manual as “not used” or “not used (spare) (Raptor)”. I am looking for a 12V ignition hot to use as a signal for a relay to turn on a device. I am planning to take a multimeter and check each of these locations to determine if any happen to have ignition switched power. Before I go freeze my balls off, has anyone located such an animal on the fuse block?

 

Well I just finished freezing my balls off with a multimeter and a shop light. This is what I found.

Fuse 14 (Micro 2) 15A (Not used, spare) (Raptor): The prong closest to the firewall is ignition switched 12V. The prong closest to the front end is not exactly 0V. When I apply the multi-meter it reads about 0.7V to start and then decays down to about 0.2V. I gave it a long time, and it never went to 0V. This seems like a leading candidate for ignition switched power, but I am apprehensive about the one prong reading more than 0V even when the truck is off.

Fuse 89 (Slotted M-Case) 30A (Power running boards): The prong closest to the firewall is dead all the time. The prong closest to the front of the truck is 12V hot all the time. This seems like a good candidate if I ever needed a "hot all the time" wire, but I would like to confirm with someone else that this fuse was included for a feature that my Raptor does not have (but I presume other F-150s do). I mean, I don't think I have power running boards...

Those are the only candidates I found for power tapping. Other spare fuse locations were dead all the time. Anybody got input on the two mysteries above? Can I safely use a power tap on Fuse 14 for ignition switched power? What's up with that partial volt reading?

 

@FordTechOne , any insight to offer?

 

@The Car Stereo Company reports in another thread that fuse 23 is ignition switched. Fuse 23 is a 10A micro 2 fuse labeled "Alt A Sensor" in the manual. Anybody know what this circuit controls?

 

Well, I'm of no help but you've done some good sleuthing here. Sorry about your balls.

 

I just wrapped up finding a switched hot and trigger circuit for when the parking/head lamps turn on for my SwitchPro 9100 on my Gen-1. These newer Fords are little more troublesome when comparing to older vehicles that's for sure with finding a switched hot. Just about all of the darn fuse ports whether inside the cab or in the engine compartment is always hot. No wonder newer vehicles' battery die/weaken if sitting for more than 2-weeks. Anyway, I know what you mean about the one side getting 12v and the other .Xv. Just make sure that you check that sub-volt side when the ignition is on and then off. That's the side that you'll want to splice to. The other complication is that these low profile mini fuses have a nub in-between the fuse spades. I think they're for alignment. I like to use these brass fuse splicers. Makes it super easy on regular micro/mini/ATO fuses; however, I had to nibble the part that gets inserted a bit to make it fit & tight.

I had the same problem with a '19 for a friend of mine but he no longer has it anymore & I don't remember which one I used to precisely tell you which one. Fuse location #14 seems to be relatively close to where I found it but it's been almost 2yrs ago. Luckily for my recent Gen-1 wiring fun, I didn't freeze like you did, but it took patience with several trips back n' forth to turn the ignition on/off with using a test-light/volt-meter.

 

Thanks for sharing your experience. I ordered a Busmann fuse tap for micro 2 fuses. I plan to try it and retest with a voltmeter to the lead from the fuse tap. Ultimately, it is connecting to a battery charger that will use it as a signal to turn on when the trigger is above 11.9V and turn off when the trigger is below 11.9V. So really, even if there is a residual potential of less than 1V on the wire all the time, that won't affect this specific function.

Still curious about those power running boards...

 

Sorry, curious about the power running boards, in what way? They are a standard feature in F-150 Platinum and Limited, if that's what you are curious about. Not on a Raptor, I think due to it being more of a street queen type of an option, wouldn't fair well off road.

 

I'm curious if this circuit can be tapped, either at the fuse box or in a harness on the truck, to be useful in some way. The fuse prongs appear to be hot all the time, so that's not much help. Wonder if there is a connector taped up somewhere on the truck that is giving 12V signals according to when the power running boards would be activated? Again, probably not useful for this project. But it's one of the few fuse locations not applicable to the Raptor that had both an installed fuse and a hot 12V signal going to it.

 

If it was 12V on one side and a solid 0V/Gnd on the other the fuse would blow the second you put it in. Think about it.