Uh, I think you have the polarity reversed. With your new fuse tap accessory fuse installed there should be power on the fuse tap wire without reinstalling the original fuse one removed. As described your fuse tap is powering through the fuse you are tapping, adding to its load.

With power off, remove a candidate large fuse from the fuse box.
Insert fuse tap with your new accessory fuse in the accessory position but not the fuse removed from fuse box.
Power on. The fuse tap wire should be hot. If not, reverse the fuse tap orientation.
Install original fuse in the fuse tap.

 

Uh, I think you have the polarity reversed. With your new fuse tap accessory fuse installed there should be power on the fuse tap wire without reinstalling the original fuse one removed. As described your fuse tap is powering through the fuse you are tapping, adding to its load.
With power off, remove a candidate large fuse from the fuse box.
Insert fuse tap with your new accessory fuse in the accessory position but not the fuse removed from fuse box.
Power on. The fuse tap wire should be hot. If not, reverse the fuse tap orientation.
Install original fuse in the fuse tap.

N4HHE,

We can agree to disagree, here. That existing fuse should be able to stand some slight extra load. You would want that existing fuse to fail when wired as I described it. Otherwise, the line to that fuse would be carrying a load that it was not designed to carry. Most accessories will not draw huge power, and if they do, they should be powered by a relay anyway, and the Fuse Tap should just switch ON the relay. The accessories which do draw heavy loads, such as heated clothing, should have an in-line fuse of their own, on the power line running through their relay(s).

I do not suggest putting huge loads on a Fuse Tap. The Fuse Tap can handle it, sure, but the rest of the wiring may not.

An extra blown fuse to an accessory is a minor bother. Burned up harness wiring can be expensive, a disaster, or both. Your choice, certainly.
.

 

Fuse taps are very handy, but as Red says, the original wire can get over loaded, so the additional circuit should be to a low current application such as a trigger wire for a relay or aux. fuse panel or a GPS or USB charger or even a voltmeter.

 

Fuse boxes have a high current buss running the length from which the fuses connect. My F-150 has at least 37 numbered fuse positions, not all are used, but they all connect to a hefty buss bar.

Fuses are sized for safety, not for extra margin that one can borrow for other purposes. The only question of capacity is whether the contacts of the fuse socket can carry extra current. This too is a serious question because ~2009 F-150 fuel pump circuit has a bad habit of burning out the fuse socket. Ford has a retrofit kit that moves the circuit to a larger fuse socket.

The configuration red describes adds a new fuse via the fuse-tap hardware in series with an existing fuse.

I say to orient the fuse-tap so it powers off the hot side of existing fuse not affecting the circuit. Original fuse only carries the original load. New fuse in the fuse-tap carries the new load.

 

The FJR is not an F150... no bus (except in the starter relay), all individual wires to each fuse for the most part.

 

These products should be banned until the flawed design is corrected. At the very least, they should be providing clear unavoidable warnings on their packaging with detailed instructions inside. These "Add-A-Circuit" type products probably junk quite a few vehicles over electrical issues. I'd avoid buying anything with one of these installed in any fuse box anywhere in any vehicle.

I've tested one of these types of products before and it's a bad design. I would expect that one of the slots would be the original fuse... for example let's say 15 Amp. Then the second slot would SLAVE off of the original. But that's not how these work. Both fuses are their own circuit. So adding another 5 amp fuse along with the original would potentially put 20 Amps over the original wire. This is really bad design! The added fuse should slave off of the original, in order to avoid the potential of running the feed wire hot. Yes, the original circuit could keep blowing its fuse, but that is INFINITELY better than creating a HIDDEN short, DEEP within the potentially tens of feet of wire harness bundles that many vehicles have. It may take weeks, months or even years depending, but a wire that runs hot, will compromise and eventually burn through its insulation... then begin working on the insulation of adjacent wires.

Even if you put something on that circuit that only draws 1.5A peak, because the smallest fuse you can install may be 5A, you have no fail-safe! So yes that 1.5A peak draw may be well within the +/- 10% margin for general engineering practice, but if something goes wrong resulting with elevated draw, the wire insulation may be damaged prior to the fuse blowing.

 

These products should be banned until the flawed design is corrected. At the very least, they should be providing clear unavoidable warnings on their packaging with detailed instructions inside.

Intuit,

(ref. Fuse Taps . . .) You raise a valid issue. I believe a heavy-rated fuse can usually spare a few Amps (not many) to power low-current accessories directly. For any heavier loads, the Fuse Tap wire should be used to energize the relay of a relay-controlled Fuse Block. This option will yield a key-switched power system to run accessories, without excessive loading on the bike wiring. I would agree, not everybody will use such options correctly, without good instruction being available. I believe the sharing of this information is the best use of bike forums like this one. I would not agree to a ban on every tool or device that can be employed badly.

 

Quick Taps:

These go by varying names, such as 'splice', 'connect', etcetera. Their appearances vary quite a bit (not just color) but the function is the same. These tend to cut wire strands, damaging the OEM wire. The wire capacity may be reduced. Over time, the product can further damage wires in automotive environments where vibration, humidity and/or flexing may be factors. The Problem with Wire-Tap Connectors | Bareass Choppers Motorcycle Tech Pages

Particularly for an automotive environment and using minimum detail, correct way is to carefully strip away some wire insulation and solder on the additional wire. I like to zip-tie the add-on to the original; keeping any stress off the joint and further securing any add-on insulation; whether that be electrical tape or heat shrink tube.


Fuse Taps:

These sometimes go by "Add-A-Circuit" or "fuse holder". These are far more insidious than the quick taps.

These products should be banned until the flawed design is corrected. At the very least, they should be providing clear unavoidable warnings on their packaging with detailed instructions inside. These products probably junk quite a few vehicles over electrical issues. I'd avoid buying anything with one of these installed in any fuse box anywhere in any vehicle.

I've tested one of these types of products before and it's a bad design. I would expect that one of the slots would be the original fuse... for example let's say 15 Amp. Then the second slot would SLAVE off of the original. But that's not how these work. Both fuses are their own circuit. So adding another 5 amp fuse along with the original would potentially put 20 Amps over the original wire. This is really bad design! The added fuse should slave off of the original, in order to avoid the potential of running the feed wire hot. Yes, the original circuit could keep blowing its fuse, but that is INFINITELY better than creating a HIDDEN short, DEEP within the potentially tens of feet of wire harness bundles that many vehicles have. It may take weeks, months or even years depending, but a wire that runs hot, will compromise and eventually burn through its insulation... then begin working on the insulation of adjacent wires; shorting shorting unrelated circuits.

Even if you put something on that circuit that only draws 1.5A peak, because the smallest fuse you can install may be 5A, you have no fail-safe! So yes that 1.5A peak draw may be well within the +/- 10% margin for general engineering practice, but if something goes wrong resulting with elevated draw, the aforemetioned insulation hidden deep within some random part of a random wire harness, may be damaged prior to the fuse blowing.

The correct way is to use the fuse tap, only with a slot that is already empty. Install ONE fuse that is ≤ what would've gone into that slot, had it been filled by the OEM. It adds complication but auto manufacturers save natural resources and money by reducing the wire gauge to only what is necessary for fuse panel slots. That's why some slots have thick wires feeding them, and some have small wires feeding them.

If there isn't a working empty slot, then the correct way is to add a relayed terminal to the battery. Your relay should be tapped into a non-critical system; for example...

 

I agree Fuse Taps are OK only if your total doesn't exceed the original wire's capacity..... many of the wires on an FJR, e.g., the power outlet are 20 gauge at best.... if the original fuse was a 3 or 5 amp (some original Gen3-up fuses are 1 amp), there's your clue. I would not add a fuse tap to a critical circuit, but the Hazard fuse might be ok to tap. Basically, I'd say the most you should tap off one is a GPS or USB charger the draws about 3 amps, 5 at the most.
Far better is a relay like Intuit says, but a bunch of those takes up a lot of room...... get an aux. fuse panel is generally what I do, eliminate all the consternation.

 

Indeed, motorcycles have little room under the "hood". Y-Connectors help minimize the amount of space needed.
I recently bought this when adding a 52MM AFR Gauge to my Motorcycle...

Amazon.com: AYECEHI 10AWG SAE Connector SAE DC Power Automotive Adapter Cable Y Splitter 1 to 2 SAE Extension Cable 10AWG 1.3ft/40cm - with Waterproof Cover : Patio, Lawn & Garden

Amazon.com: AYECEHI 10AWG SAE Connector SAE DC Power Automotive Adapter Cable Y Splitter 1 to 2 SAE Extension Cable 10AWG 1.3ft/40cm - with Waterproof Cover : Patio, Lawn & Garden

www.amazon.com

It is bigger than I wanted. But if push came to shove, could've cut it down.

 

deleted.

 

Pextor in another forum pointed out that you might be able to install them either way; space provided. (no space for this in either of my use cases)

Quick & dirty diagram I drew...

 

Pextor pointed out over in another forum that these might be installed in either direction. Just happened that in my use cases they would only fit in one direction due to obstruction. (Relay/Cover/Fuse in the way) Fortunately I had an empty slot to use instead.

Quick & dirty diagram I drew...

 

Pextor pointed out over in another forum that these might be installed in either direction. Just happened that in my use cases they would only fit in one direction due to obstruction. (Relay/Cover/Fuse in the way) Fortunately I had an empty slot to use instead.

Intuit,

My first post here (#1) also shows a Fuse Blade Tap, which can provide low-Amp switched power to the relay coil of a relay-controlled Fuse Block. The Fuse Blade Tap is designed for minimum-space applications, and the connecting blade can be bent to either side across the top of the original fuse. It would be wise to use an in-line fuse holder and low-amp tubular glass fuses in the resulting key-switched power line. The newly added Fuse Block can supply fused power to the accessories, safely.

 

Posi-tap is my go to now-a-days.

2 dupe threads merged so people following this will get all the answers in 1 place.