Mystery fuse under the hood.

[firefighter_2000]

Found a fuse on the passenger side under the hood recently. It's taped up into the harness that runs there already, so I can't really tell where it's coming from or going to. Can't for the life of me figure it out goes. Anyone have any ideas?
Craig

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[terb]

Try pulling the fuse and see what stops working!! Then report back with your findings............:-{}

 

[firefighter_2000]

Tried that... Couldn't find anything!

 

[MattandLana]

Look I know it's not much help, but you could work your way through the wiring diagrams here. It would take a while to look at all the fuses, but the "connector location" feature (sample below) may help you identify it eventually. Sadly, very sadly, the schematics don't seem to be interactive - it would be neat if we could click on the pictures and be shown what the connector was!
best I can offer sorry.
Good luck.

On edit: I removed the image because the one I found below is on-topic.

 

[MattandLana]

Hey I was mucking around with the TechAuthority wiring diagrams (fantastic resource, fantastically awful interface) trying to see how I could use it for my own needs, and I think I might have found your fuse! It might be D845D. Check it out:

And in closeup:

On edit: Changed the images

 

[gsbrockman]

I've not looked at the PDC very closely, but I wonder if this fuse has the same function as the IOD (Ignition Off Draw) of previous years???

 

[Kirwin]

Firefighter2000. What radio do you have in your truck? I'm curious if this is something left over from an old wiring harness revision that they just abandoned in place, thus the reason it appears to do nothing when you pull the fuse. Thanks for staying with the search Mattandlanna. I off to look truck. Ken Irwin

 

[MattandLana]

... I wonder if this fuse has the same function as the IOD (Ignition Off Draw) of previous years???

Firefighter2000. What radio do you have in your truck? I'm curious if this is something left over from an old wiring harness revision that they just abandoned in place, thus the reason it appears to do nothing when you pull the fuse. ...

This is all theory for me because my truck is somewhere mid-Pacific right now, and remember I'm a newbie, AND searching the schematics which come up on my own VIN, but, for what it's worth ...

gsbrockman, no hits in the TechAuthority schematics on "IOD" or "Ignition Off Draw". The only hit on "Ignition Off" takes me somewhere different with no apparent inline fuses.

Ken and Firefighter, the schematics (for my VIN remember) show this fuse (if I've got the right one) as being the main power feed to both the base and premium radio, see the screenshot below. The D845D fuse is on the far left, and the blue box at the bottom is the radio. If I'm reading it right this fuse is the sole power source for the radio. (Note: I can't upload the full schematics pdfs (hey, when you try to print from the TechAuthority wiring website it downloads them as high-res pdfs - neat!) because they're too big but I've tried publishing them here and here. First time I've tried sharing from G-Drive so not sure if it will work. You need to download them to get best resolution.)

Here's the extract from the schematics:

 

[firefighter_2000]

Well... I went back and checked again and it ended up being the radio... I usually leave the screen in the off position, and just assumed it was still where I left it. I never imagined that the fuse would have been for that. I was searching for an accessory add on that might not be working, like the seat vent/heat, etc. I have the UConnect 8.4AN radio. Seems kinda cheesy to have the fuse there and not located in the PDC on the drivers side.
Thanks for the clues!

 

[MattandLana]

Cool. We all learned something. I agree, very weird location. OK, different trucks come with different radios, but how many years has it been since a car/truck came with no radio at all, making the radio an add-on that doesn't deserve its own spot in the fuse box?

There, that should get some "I remember when"s going! Has for me, thinking about my first car with nada; and how flash I felt with my second car once I installed a cassette player under the dash and balanced some speakers on the rear parcel shelf. And (will this trigger a memory?) how it was one of those then-newfangled auto-repeat units that just kept looping, so when you gave your mate another lift a week later he said "Hey, what a coincidence, you were playing this tape last week too ...".)

 

[JLandry]

...once I installed a cassette player under the dash...

Cassette player?

Sounds like you may have missed the wonderful 8 track tape player days. It also repeated endlessly, but because the magnetic tape inside the cartridge was one long continuous loop.

John L.