Unused Fuses
 

As this is my first post I will say, greetings fellow fit owners. I own a 2010 5-speed automatic base model. The modification I'm looking to make to it is a powered USB hub device for the purposes of an onboard computer.

My plan is to use a fuse tap to run a circuit from my fuse box to the upper glove compartment, wherein I would locate the powered USB hub. Presently, I have the USB hub receiving power from the 12V socket, but the cable is unseemly. I'd prefer a solution where I can leave the hub inside the glove compartment and it turns on when I start the vehicle, OR it could have its own switch to control ON/OFF.

My question is the following, on my Fit I count 11 unused fuse slots as follows (highlighted on this PDF diagram):

• 25 - Not Used
• 31 - Not Used
• 40 - Not Used
• 41 - Not Used
• 42 - Not Used
• 45 - Not Used
• 46 - Not Used
• 53 - Not Used
• 54 - Rear Defogger (if equipped)
• 55 - Heated Mirror (if equipped)
• 62 - Not Used

Testing these fuse locations with a voltmeter I determined that they are ALWAYS on, with three exceptions: 31, 54 and 55. Fuse locations 54 and 55 are ALWAYS off (regardless of ignition). I did not test location 62 as it is difficult to reach.

Location 31 is... confusing. It appears to be ON when the vehicle is started. However, when I shut off the vehicle it seems to retain power, but after a minute or so the location seems to lose power. Is this behavior normal?

In case you're curious as to how I tested (to ensure I'm not doing something asinine), there's a large bolt at the very top of the fuse panel, you can see its hole in the fuse diagram. I placed my negative probe against that bolt and the positive probe in the fuse slot. I tested these multiple times to be certain.

So, to sum up, these are my questions:
Can I run a 10 AMP (drain on the circuit will be significantly less than that) fuse with a fuse tap through any of the ALWAYS on fuses (installing an ON/OFF switch would be a necessity to prevent battery drain of course)?
What's up with fuse location 31? Is it on/off or something else? (Previous question also applies to this one)
Is there a way to turn on fuse locations 54 and 55? (First question also applies assuming this location can be activated)

In case you're curious this is the USB hub in question -> Mountable 4 Port Rugged Industrial USB Hub

I appreciate any help/suggestions.

why not just use an add-a-circuit, hook up either a micro or mini usb hardwire box you can buy from ebay, and be done with it?

This works great, doesn't cost much, and requires no labor. If you really need four USB connections, you could plug in separate USB adapters in the 12V. sockets.

@kenchan: Aren't a fuse tap and an add-a-circuit the same thing? I already own the USB hub, so it's not a question of purchasing it. Can I hook up the fuse tap/add-a-circuit to these unused fuse locations or is that a no-no? The reason I need a powered hub and not just a USB power port is because the computer I intend on using requires a powered USB hub (its ports don't provide enough juice for certain devices).

@Triskelion: I want to conceal it in dash. I also don't want visible wires. Though your suggestion is perfectly feasible, (and currently what I'm doing), I don't really mind the extra labor if it provides a better overall look, and it's less worrisome in terms of what's visible from the exterior of the vehicle.

While I appreciate the alternative suggestions, I'm curious moreso about these unused fuse locations and how to leverage them.

as far as the owner's manual for the 2010 Fit goes... you missed #4. it's also not used.

#54 and 55 most likely rely on another circuit being ON before they get power. I think #9 would be the same, always OFF, until you turn on the headlights to LOW beam. #54 and 55 are specifically heating elements, so it could be a way to lessening the likelyhood of it burning up.

as for #31... it could be on a circuit similar to the dome light or window switches. you'll notice, that if the dome is set to door, then it doesn't turn off right away when you take your key out and close the door. And the window switch retain power after taking the key out until you either open a front door or a timer expires. though, I think the window timer is longer than a minute.

Couldn't find anything about fuse 31 on a GE. I did find out that on the GD it is a timed circuit as well from old posts here on FF.net.

I am curious what that location is for, wish I had a wiring diagram :mad:

the skyroof? or more specifically, the inside panel.

Ohhh that is one timed item that is missing on the USDM Fits I didn't think about, good call Goobers :)

hmmmmm
I think that might be a good match... gotta look in to it more when the shop installs it.



Not sure if this helps much, but I installed my LED keyring with a add-a-circuit (10amp fuse, iirc) as shown here:
Since I got a working unit I've had no problems with drain or otherwise with that.
I plan on using atleast one more to reinstall the OEM aux which I removed when I installed the JDM cig lighter accessory.

If I'm not mistaken some one else just recently used the same tap to add a powered usb hub.

@Goobers: You are correct sir, I completely glossed over fuse #4 when I was looking at my fuses. I blame tunnel vision and uncomfortable body position. In any case fuse #4 is ALWAYS ON.

@FitStir: Am I correct in assuming that's fuse location #40? Also, does your LED keyring come with its own controller for on/off states?

It has a circuit board, which basically controls the color of LED when the car is locked(Red LED)/unlocked(Blue)/key in ignition(the only time the LED is off). It's actually on all the time, and I've left my car parked for over two weeks sometimes with no noticeable drain on the battery. Car starts right up.

I'm not actually sure which fuse location it it, but if you read niko's thread it might show you better. It's on the right side of the fuse box. If you like I can double check in the car to be sure of the location #.

No worries FitStir, upon closer inspection of the photo you quoted (and reading through niko's thread as per your suggestion) it does indeed appear to be #40.

Updated fuse diagram to better reflect the unused locations.

Thank you... your diagram will make a nice quick reference for me for future mods. :wavey:

4 Port USB Hub
 

Here is the end result of my fuse questions. Basically, it is a 4-port USB hub that will be used to power a mini computer. However, it can be used to charge other electric equipment. The beauty of it is that it's modular so it can be removed from the vehicle should you require a hub elsewhere. The second point is that the connection that remains within the glove compartment is now available for other such devices to be constructed using a similar connector. Be careful with this, as if the connector is not being used, you essentially have 12 Volts LIVE in your upper compartment and shock or injury could occur.

Tools required:
#2 Phillips Screwdriver
Wire Stripper/Crimper

The sequence of steps can be viewed here. I did not include instructions on how to assemble the hub because it's somewhat of a pain to take apart. However, the 12 V port into your upper compartment should be more than useful for a variety of mods.

Lastly, I used red cable for both the positive and negative terminal. This is a no-no. A black cable should be used for the negative terminal, precisely to denote ground and avoid confusion. However, budget kept me from doing otherwise. I would've preferred to use 12 gauge wire as well, but I couldn't find connectors that would fit the rocker switch's terminals that weren't 14-16 gauge, thus the decision to use 14 AWG wire. I used a 7.5 amp fuse (even though the add-a-circuit is designed for up to 10 amps) because I figured better safe than sorry, and none of the devices I intend to connect (even simultaneously) draw that much current.

The popular question from the few folk I showed it to was "will it charge my cell phone?" The answer is, it depends on the phone. Some cells will charge off any USB port, but others require driver installations if you're charging it from a computer/hub as opposed to a wall charger.

Real nice job on this DIY. I would suggest you put the photos up here direct so more people will see your good work. Some won't bother with a link to them.

I know you got the mod done, but just as a curiosity I decided to compare these with the GE8 ESM (the one from the thread).

For one version of the Japanese GE8 (some of these features are dependent on what options are on the car)... different locations for the Thai made & other versions.

• 31 - 7.5 A - Engine oil sensor

• 40 - 20 A - Driver's seat heater (Via driver's seat heater relay), Front passenger's seat heater (Via front passenger's seat heater relay)

• 41 - 10 A - Front position lights (Via daytime running lights relay), Taillights (Via daytime running lights relay), License plate lights (Via daytime running lights relay)

• 45 - 15 A - Driver's door unlock relay, Fuel lid actuator (Via driver's door unlock relay), Driver's door lock actuator (Via driver's door unlock relay)

or

• 45 - 20 A - Front super locking relay, Rear super locking relay, Driver's super locking actuator (Via front super locking relay), Passenger's super locking actuator (Via front super locking relay), Right rear super locking actuator (Via rear super locking relay), Left rear super locking actuator (Via rear super locking relay)

• 46 - 20 A - Sunshade motor/control unit

• 53 - 10 A - Transmission control module (i-SHIFT system)

• 54 - Rear Defogger (if equipped)

• 55 - Heated Mirror (if equipped)

Locations 4, 25, 38 & 42 are not used for anything

The position 55 should be on once the antifogger relay is turned on at the AC control board no?

Yes, I believe Alpina confirmed it in his DIY... https://www.fitfreak.net/forums/2nd-...smart-key.html

And 40 is where you would connect your seat heaters when you get them.