Hi Darren
It just so happens that I was tidying up the workshop today and came across an unfinished project involving an ST1100 Fuse Box. So I thought I'd investigate for you. IT may not be the same as yours, but if it is, this may provide you with some useful information. Certainly this one has the Ign as the 4th one down. The 7 in order are 10A Meter, Tail, Position / 10A Indicator Horn / 10A Turn Stop / 10A Ign ACG Starter / 10A Fan / 10A Clock / 20A Headlight. Not that it matters much if the fuse box design is the same. I haven't a clue what ACG is - perhaps ACC spelt incorrectly ?!
You could certainly try cleaning up the contacts by inserting a blade a few times - depending on how corroded it is. Another alternative is to use a cut down emery board or a nail file. Be careful not to spread the two sides of the blade though. Also these terminals will be live. Disconnecting the battery is a good idea.
I suspect though, that the intermittent connection is caused by the damaged holder. Some pics to explain.
First an image looking into the fuse box from the top with all of the fuses removed. I have also removed one of the blade terminals - the one with the red line pointing to it. More on that later.
View attachment 234517
Here is the actual fuse blade terminal taken out of the fuse box, viewed from the side. Note the little lug protruding from the bottom. Unlike many terminal, this lug will not bend out of the way.
View attachment 234514
Here is the same Fuse Blade Terminal Viewed from the top side of the previous photo. Note the sprung bent contact which has enough spring in it to touch the opposite side. The fuse blade slots in there (from the left of the photo). It is the metal on both sides where the bent part touches the top part that needs good electrical connection with the blade.
View attachment 234515
Now back to the first image. I suspect that the terminal is not locking into its proper position, so that when you put the fuse in, all it is doing is pushing the terminal in the photo above out of the back of the fuse box. My guess is that when you replaced the fuse, and it worked, the fuse box was not mounted on the bike, but was in your hand - and that prevented the terminal from escaping out of the back !
The red line in the first photo is pointing to a plastic moulding which springs up from the bottom of the hole where the fuse blade terminal lives.
That plastic 'tang' clicks into place behind that little metal lug that I pointed out in the second photo. It is located at the lower side of the slot in the bottom row, and in the top side of the slot in the top row. You can just see the end of it peeping out of the darkness in the position above the one labelled with the red line. It is this plastic 'tang' which springs up behind that metal lug when the terminal and wire is pushed into the fuse box. Thus locks the terminal in place and acts like a latch on a door or on a ratchet. It has to be gently moved out of the way to release the terminal again. If the fuse box is damaged, then that plastic tang may not be there to hold the terminal in place.
See the diagram below. It represents the terminal (as shown in the 2nd photo) inserted into the fuse box.
In order to remove the terminal from the fuse box, you need a small screwdriver. Push the wire to which the terminal is connected into the fuse box (to the left in the diagram) - it will only move a fraction, but it helps. Gently slide in the oange handled screwdriver with the blue blade alongside the terminal ( from the rear of the fusebox where the wires enter) and allow it to push down on the plastic. Don't use force, you want it to spring up again. Leave the screwdriver where it is, but pull on the cable. If it doesn't come, you need to push the screwdriver in a little further and maybe press the blade down a bit more. But the trick is to keep the driver pressing on the plastic tang as you pull the wire. Once you feel it is free, then let the driver come out.
View attachment 234518
[Update]
24 hours later, I've just tried the above method again, and the second time, this was not as easy. So I tried from the front. There is a tiny lip on the plastic tang which you can just about make out when viewing the fuse box from the fuse side - with a bright light and a magnifying glass. If you put a screwdriver in from the front and press down on that lip, while applying gentle pull on the cable from behind, you will feel the terminal release. I got a much better success rate doing it this way than the way I described first of all. - But both methods work.
View attachment 234524
[/Update]
If you intend to do this to check out the terminals, then I suggest disconnecting the battery first, and only remove one terminal at a time, before putting it back again. Note that there are two pairs of terminals which are connected together. You will see the connecting strip if you look at the back of the fuse box where the wires enter. They are (on the Fuse Box that I have) the '10A meter tail position' linked with the '10A indicator horn', and the '10A turn stop' linked with the 'Ign, ACG, Starter'. So if the fuse box is damaged at the 'Ign' terminal and the terminal isn't being held in place properly - it can't actually come all of the way out, because the terminal next to it will be holding it in. It may be that all you have to do is make sure that this fuse is always inserted when you can get your fingers around the back to keep the terminal in place. (Those wires and terminals will likely be live all of the time, whether or not the ignition is on, so be careful - disconnect the battery).
The purpose of the metal connecting strip is to provide power to 2 fuses from one heavy duty cable. One of those terminals will therefore not have a wire connected to it.
However, to get these pair of terminals out you would need to release two plastic tangs simultaneously.
But, I suspect that you would get away without taking any terminals out, and just cleaning up. Which sort of negates all of the stuff i have said so far - but the information is there, it may be of use, and at least gives you the option !
Grease / oil ? Apply some silicone grease to the terminals and to the blades (its supposed to be dilectric grease, but I've never had problems with silicone). If there is enough spring in the contacts it will clear the grease away where it needs to make contact. If you want to protect the connections at the rear I have used that white spray grease, comes out liquid but turns thick and sticks pretty well. I use it on my banjo bolts to stop them going rusty over winter.
I'm not sure that info about the grease is particularly good advice - others will chime in if it is a complete no-no - but its what I've done for the last umpteen years, and it is infinitely better than the letting in salt water that kicks up off the UK roads.
