Chinook RV

Here is the "Modified Vehicle Schematic." From what I can tell, this encompasses them all (?). But I "squared" the one that looks most interesting. The connector number in the circle is, I think, the one we've been speaking of under the hood. But see the one I made an arrow and question mark to? "Under dash." Can that be something? They all seem to lead to/from that same 50 amp fuse. You can see more if you look up the "FUxxxxxx" part numbers on the main list (second photo previous post). Note that you can click twice to make it even larger.
And here is the complete version of the connector under the hood that we've already been working with:

Great job Blue! I've outlined what I think is important. The two connectors both refer to Yellow being the "battery feed" and the orange as the ING. CONT. FEED...Does that mean Ignition Control Feed? My two wires are both yellow and orange with yellow being hot and orange being control or switched. These at least have similar functions if that's what this means...Getting closer I think

I think you are on to something, it is showing something we haven't seen yet which is great. I found this E350 image that shows fuse links in the wiring. I think both of us are showing that there are other links in the line that can be broken. Are you thinking the same Blue? I'm starting to smell a solution....

I've also outlined an interesting area on your graphic which shows an Orange line I believe...

So, the money question for me is.....What is a fuse link and where can a man find one?

I like to think we're homing in on it

The links you show are on "trailer circuits" though, right? Of course that means they might be somewhere else, too.

I bet "Ing." is a mis-typed "Ign."

Here is another thing I'm thinking. What gauge is that orange wire from Ford. Are they calling out 12 gauge? That seems light for 50 amps. Also, if you look just below the question mark I put below the arrow on that diagram with the "squared" area, it seems to say the maximum "shared" current load for that "37" circuit is 25 amps. Okay, so two times 25 is 50, but at least in my world you then have to "fuse down" when you split that to two 25 amp circuits. Unless I'm missing something.

The area on the right that you highlighted. That looks like it is supposed to be for trailer stuff, but then since Chinook used the Ford trailer line for their own taillights, who can say what they might have re-purposed?

Cross referencing the one "under dash" part number to the other sheet that shows them all (which I think is the second drawing in the first post, right under the huge one), there is one (another?) orange, 25 amp, ignition controlled feed. That *also* mentions "37 circut."

It's all a bit confusing, but it does seem like the answer might lie somewhere in the combination of these Ford drawings and an as-built actual Chinook.

Maybe this will be the one thread on power steps that does not peter out with no conclusion (as so many did when I Google searched the web). Sometimes I wish there were a law that said the person has to come back and say what the outcome was --- even if that was "no outcome."

Watch this quick video on Fused Links Blue and tell me we aren't close. Didn't even know these existed but they look heavy enough to deal with what you are referring to I think...

https://www.youtube.com/watch?v=-SpsSRGfDQI

Oh, PS on that last post. Note that the connector F7UB-14A411B is a big rectangular one with 6 wires. But then ALSO note where they show it circled up to the right and it may not be on "cutaways." They specify the A one. But "gas RV preps" DO get the B one. Since we have a cutaway, but it's an RV..... I don't know?

Interesting. I had heard of fusible links but didn't really know much about them. Maybe there is more to it, but right now they seem like a bad type of fuse. Because, if there was a "real" fuse you could just put a new one in (and obviously if it blew again you'd have to find the real problem, if it was more than just a one time thing). But with these, you don't have any way to replace it without "doing wiring." 'Course it's easy to install them in the first place. And maybe there are other benefits I don't know about.