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

[GordoJay]

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.

True, but if it was 12V on one side and floating on the other, it would measure a solid 12V on both sides ... something odd is going on.

 

[isis]

True, but if it was 12V on one side and floating on the other, it would measure a solid 12V on both sides ... something odd is going on.

I think he measured the socket without the fuse. Nothing weird at all.

 

[GordoJay]

I think he measured the socket without the fuse. Nothing weird at all.

Gotcha

 

[FordTechOne]

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 F14 in the BJB (engine compartment, RH side) powers the Vehicle Dynamics Module (VDM), which controls the Live Valve suspension. It’s hot in Start or Run. Are you sure it’s F14?

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...

Correct, F89 is for the Power Running Board Control Module (RBM), hot at all times. Since Raptors are not equipped with power running boards, the fuse is not used.

 

[FordTechOne]

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.

The circuit powered by F89 is for the RBM; without that module there is no switched power output.

 

[FordTechOne]

@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?

Fuse F23 in the BJB is hot at all times and powers the generator regulator A sense circuit. It would not be wise to tap into that circuit.

 

[DINOZR]

Fuse F14 in the BJB (engine compartment, RH side) powers the Vehicle Dynamics Module (VDM), which controls the Live Valve suspension. It’s hot in Start or Run. Are you sure it’s F14?

Thanks for the feedback. Here is a screenshot of my printout of the 2019 manual and the notes I took at top. I am as certain as I can be that it was fuse 14.

 

[DINOZR]

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.

I am a mechanical engineer, not an electrical engineer, so I'm outside my lane, but I suspect that is not true. I think inserting the fuse would complete the circuit and then the fuse would either remain functional or blow depending upon the amp load in the circuit compared to the amp rating of the fuse. I certainly could be wrong.

 

[The Car Stereo Company]

i was going off memory. i will have to double check the fuse location. seems my memory is off a bit......

 

[isis]

I am a mechanical engineer, not an electrical engineer, so I'm outside my lane, but I suspect that is not true. I think inserting the fuse would complete the circuit and then the fuse would either remain functional or blow depending upon the amp load in the circuit compared to the amp rating of the fuse. I certainly could be wrong.

I am an electrical engineer. If you have 12V on one side and a ground on the other and insert a fuse the fuse will blow. 12V drop divided by zero resistance (a fuse is a short) equals infinite current (blows any fuse regardless of rating).