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Discussion Starter #1 (Edited)
While doing the headlight wiring upgrade on my 1050 Sprint ST I made a few changes to use the existing headlight fuse normally made redundant by the mod. Once I’d started I realized how easy it would be to add more circuits using the spare slots in the fuse block. From time to time we see posts asking about adding circuits to the original factory fuse block so I’ll share the info.

For those who aren’t familiar with their Sprint electrics I’ll point out that Triumph already made provision for some accessories. Connections for GPS or heated grips are already pre-wired and we have an auxiliary outlet as original fitment. If they are not enough an aftermarket fuse block can be added – the space behind the screen seems to be the popular location. I wanted the headlight fuse to be easily accessible and to keep everything in one place so I focused on using the existing fuse block.

The first task was to remove the fuses, unclip the terminals and pull them out to take a look. Headlights are protected by Fuse 1 which feeds via a purple wire to the starter relay (to cut the lights during starter operation). Replacing that purple wire with 12 gauge wire looked like an easy job.

The input side was a bit more complicated. Three terminals are ganged together and fed by a wire from the charging/battery circuit. I needed to separate the input terminal for Fuse 1 and attach it to the new supply from the battery.


Shared input to Fuse 1, 2 & 3

Those terminals are soft metal (I assume tin-plated copper) so a quick snip with a pair of end-cutters removed Fuse 1 input terminal from the trio. I clicked the remaining two co-joined terminals back into the fuse block to restore connections for Fuse 2 & 3.

Now all I had to do was attach the two remaining terminals to the ends of the new wires for input and output of Fuse 1 and wiring to the headlight fuse would be complete. However, there was a bit more work to do to add a couple of new circuits.

Adding New Circuits

ABS-equipped Sprint STs have two spare slots that are used as parking spaces for spare fuses. Non-ABS bikes have two more unused slots where ABS System fuses (Fuse 4 & 5) would normally live. In the photo below you can also see two larger slots at the right end (bottom as mounted on the bike) of the fuse block that appear as if they’re for larger ATO/ATF full size blade fuses. I ignored those because I couldn’t find suitable terminals.


Unused slots at the left end of fuse block usually hold spare fuses

To use the other spaces it should be a simple job to crimp terminals onto my new wires and I’d have my new headlight circuit plus two additional circuits. All I needed was some spare terminals and I’d be good to light up Las Vegas! A slight problem though: I couldn’t find those terminals. Solution – buy a used harness. More about that later but let’s get on with the job.


Terminals ‘R’ US – a used harness provided the bits I needed

I had three circuits to feed but didn’t want to run separate cables from the battery for each of them. I chose to run a single feed from the battery and split at the fuse block. To make sure I didn’t compromise the headlight wiring upgrade I used 10 gauge wire. At the fuse block I used a double terminal to provide input for Fuse 1 and the spare slot next to it. To feed the other new circuit I simply looped a few inches of wire across to a single terminal to go in the spare slot next to Fuse 6. Describing it is harder than doing it.


Diagram of fuse block wiring for additional circuits

The output side was simple - 3 new 12 gauge wires to provide fused circuits for headlights, high beam and horns. I’d previously installed FIAMM horns running via a relay off the heated grip circuit but decided to revise that with a new circuit that can also be used for any electrical equipment I might add in the future.

Test It

With the new terminals clipped back into place I checked the circuits to make sure everything was in order before reconnecting the battery (hey Champ, you did disconnect the battery didn’t you?). Happy that all the readings were good I could complete the rest of my wiring before I wrapped it all up and tied it into place.


New wiring wrapped and tied with fuse block clipped back into stowage compartment

Finally, one more small finishing touch; I made a new fuse ID label for inside the fuse block cover. OK, it’s not an essential component but that’s the way I like to do things.


Finishing touch – new label inside fuse block cover

Some thoughts

I said earlier that I bought a used wiring harness. That may seem like an expensive way to get a few connectors but I managed to find a damaged harness. That made it fairly cheap but still a perfectly good source for raiding bits and pieces. The spare harness let me complete the job the way I wanted – new fuses contained in the original fuse block and a professional-looking job that doesn’t look out of place alongside the OEM wiring. I also got the relay holders with their rubber mounts and a stack of spare connectors for future projects so for less than $30 (with shipping) the used harness worked out well.

I doubt that many people will actually do this but if, like me, you’ve ever looked at those spare fuse slots and thought about using them then maybe these words and pics will help.
 

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Nice one, Champ! :D

Cheers,
-Kit
 

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Discussion Starter #4

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Another excellent writeup from Champ!

It became apparent from his initial offering that his "how to do it" articles would set the standard. This one continues to reinforce my opinion and appreciation.

I have had paid subscriptions to services which never provided anything of the quality of Champ's offerings.

Now the justification for those horrendous maritime fuse blocks has been eliminated. ;)

Thanks, Champ.
 

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WOW! another excellent write up by Champ. The time you spend putting these write ups together is much appreciated. Thank you.
 

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Discussion Starter #10 (Edited)
Next Question....

I'll answer this question before someone asks - "how do you release the terminals from the fuse block?"

They're held in place by plastic tabs that are part of the fuseblock. Use a small screwdriver (very small) to push the tab away from the terminal as you pull the terminal out the back of the fuse block.

All terminals in the center rows are single terminals for circuits going out. The two outer rows are inputs and some of them are joined as shown in the first photo. They can be identified by looking at the back of the fuse block where the wires come in/out. To release those pull lightly on wire as you release the two or three clips in turn. You can do them one at a time and the wire and terminal will pull out the back of the fuse block quite easily. You do not need to have a tug-of-war with them - if the terminals don't come out with a light pull on the wire then you haven't released the clip correctly.

 

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To use the other spaces it should be a simple job to crimp terminals onto my new wires and I’d have my new headlight circuit plus two additional circuits. All I needed was some spare terminals and I’d be good to light up Las Vegas! A slight problem though: I couldn’t find those terminals. Solution – buy a used harness. More about that later but let’s get on with the job.


Terminals ‘R’ US – a used harness provided the bits I needed
I can concur that it's a real challenge to find these terminals. This molex comes painfully close:

http://www.molex.com/pdm_docs/sd/354136102_sd.pdf

But is not identical. There is a chance it may fit, and I'm going to attempt a sample request.

I found nada while power-googling all the other usual suspects. There is also a Korean supplier of similar fuse block box receptacle crimps, but good luck getting those.

They are 8mm pitch, mini fuse terminals or box type crimp receptacles.
 

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Excellent write-up there, I have found it very useful as i'm doing some repairs to the wiring loom of my D650 and also upgrading/modifying the headlamp feed.

Anyway, I have ordered some of these in the hope that they will fit the fuse boxes on my bike, I will update if they're worth buying or not when they get here.
 

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Excellent write-up there, I have found it very useful as i'm doing some repairs to the wiring loom of my D650 and also upgrading/modifying the headlamp feed.

Anyway, I have ordered some of these in the hope that they will fit the fuse boxes on my bike, I will update if they're worth buying or not when they get here.
Good find, please do check back in. My Molex sample request has gone nowhere.
 

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Discussion Starter #15
Here are some pics of the co-joined fuse block terminals that may help identify them.

The second shot is a close-up showing some ID marks that appear to read "HL". I did much searching online and also sent this shot to Jim at Eastern Beaver. Even with his knowledge of such things he couldn't identify these terminals so it seemed to be futile mission for me to continue. Buying a used wiring harness became the best option available.




 

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I will see what the ones from the link above look like but I do have other leads to follow too, BMW use micro fuses too and you can order individual contacts through your local dealer... It's just a matter of finding the one you want on their parts system which is not the easiest to navigate.. realoem.com
 

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Update time

The ones I ordered from Vehicle Wiring Products won't do it, however, they do have the same connectors as mentioned in the PoleVolt link above. For some strange reason I can't find them on the VWP site but they are in the catalog.

The old is still connected to the loom in these pictures.


 

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That's the ones as in the PoleVolt link, they need the tang removing from the back and a slight shave as shown in that picture.... They are a good grip on the fuse, a snug fit and after the shave to the underside they snap in on the existing latches... Close enough.
 
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