Never trust a bl**dy fuse...

[Guest]

G'day all,

Just thought I'd write up the latest baffling GS tale here. If only to 'workshop' it with y'all and save myself on dosing up on too much medication.

Well I was just mellowing out in the garage tonight, checking valve clearances on the old GS1000S. All was going well; I even had the correct shims in my motley little shim collection, so I was mighty chuffed. Then I turned my hand to balancing the carbs... and again, all was going well, until suddenly I noticed the green neutral light go out while I was giving the carbies a final fiddle.

Hmm, I thought. Upon checking things further, I found that the oil pressue light didn't work either... or the indicators... or the horn... or the brake light. Bother. First thing to check was the fuse box.

Ah yes, I said sagely, as I gazed at a fried signal fuse. Whipped it out, located another 10A item in my goodly little fuse collection. And then went to see what difference that made.

In a word, none. Bother. Out with the multimeter. Promptly checked each fuse for continuity -- which they all had. Bother.

So then I spent THE NEXT TWO HOURS poking my way through the wiring harness, looking for a busted or frayed or earthed wire -- all to no avail.

In desperation, I checked the fuses AGAIN. "Got ya you little rotter!!" I thought as the signal fuse returned a blank. Not having any more 10A fuses, I got the little rotter and gave it an end-on-end tap with a pair of pliers (nearest tool to hand at the time). Now the little rotter had continuity.

Put it in, and... (drum roll)... EVERYTHING WORKED. I didn't know whether to scream with joy or frustration.

Of course, something in the blasted harness somewhere caused it to fry in the first place.

But in the meantime, comrades, never trust a fuse. Not even a new one. Not even one that your multimeter says is OK. Because the gremlins will only be laughing at you...

[SPARKSS]

"never trust" is probably not the best piece of advice. DO TRUST your own knowledge and theory.....and next your test equipment (which you can verify on other circuits). What I wouldn't trust......is that fuse that you tapped-back-together, as it has likely become unsoldered or broken inside (as you found)....which WILL fail again.

Glad you found your problem. Other types of fuses have their own gremlins.....ATO (ATC etc) plastic fuses, and their variants for example, will tarnish or corrode at the flat blade terminal....increasing resistance slightly....which causes heat to be dissipated at the blade....causing the holding terminal to weaken....and downward she spirals until the melted and unworking mess becomes apparent. In your case, with a glass fuse, the same thing happens often, except that the only thing that melts (or sometimes unsolders) is inside the fuse and nothing is seen except that the fuse becomes open. Also occurring is that the bonding between the metal caps and the glass tube lets go....working the element inside and allowing moisture.

Removable fuses (and indeed any sort of connection) screwed into sockets (big 'n small).....circuit breakers.....you name it.....given a little bit of tarnish, corrosion, weakened springs....and current x voltage across them - are all prone to similar types of failure - as you've experienced.

[Steve]

Now ... if you enabled continuity by banging on the fuse, I'm not so sure I would trust that fuse, either.

Evidently there is an 'iffy' connection inside the fuse. Either replace it now or carry a spare and hope it doesn't quit at a bad time.

.

[flyingace]

Now ... if you enabled continuity by banging on the fuse, I'm not so sure I would trust that fuse, either.

Evidently there is an 'iffy' connection inside the fuse. Either replace it now or carry a spare and hope it doesn't quit at a bad time.

.

Sage advise. One bump and out go the lights.

[Jethro]

Never trust a wad of tinfoil jammed in the fuse holder... ok, I haven't done that... much.

[Planecrazy]

On the other hand, maybe there's absolutely nothing wrong with that fuse ... maybe the fuse block connection is corroded and tapping on the fuse scraped the contact area clean.

The moral of the story is, replace the fuse AND carefully clean the fuse block contacts to ensure continuity...

Regards,

[simon_C]

i was wondering why i kept blowing fuses on my 400, turns out the wire going into the front brake light switch was really frayed at the connection in the brake lever and was shorting to the handlebars. promptly re-soldered that back up and all is now well...

[Planecrazy]

By the way, I forgot to mention that several people over the past few years have had complete fuse block failures, and have replaced the entire fuse block with nice new ones with more circuits available to use for aftermarket mods. This is an especially useful upgrade for those whose bikes still use the older style glass fuses.

If you're having mysterious electrical problems and can't seem to find any obvious problems, checking the health of the fuse block itself (especially the connections coming out of the back) might just be the answer.

Let's face it ... on our twenty+ year-old bikes doing a complete replacement of all the wiring is never a bad idea. I haven't done it yet, but it's definitely high on the list of worthwhile projects.

Regards,

[tfb]

Thanks for all the sage advice there blokes. No, I won't be trusting that fuse either, of course. But it's all I've got at the mo. Will have to do until I can swing by a servo later today. And yes, I will be pulling out the fuse box for a closer examination, etc.

The bit that really got me was the fact that a new fuse was a dodgy fuse. (I always avoid the ones that are just pressed together, and I get the ones that have soldered end-pieces, as they tend to be a whole lot more reliable.) Now dodgy fuses aren't unheard of, I know... but then it tested OK... and then it didn't, but not until 2 hours of fruitless scavenging around the wiring loom had passed.

That's 28 year-old electrics for you.

[Steve]

Since we're on the topic of fuseboxes ...

I was recently made aware of a nice product. Fuzeblocks. Not cheap at $80, and currently out of stock. This is a guy that has them made in small quantities, as he is able, not a large mass-produced operation. It has a built-in relay and SIX circuits. Note that each circuit can be either constant-power or switched-power. Tidy little package, not much bigger than a GS fuse block.

I think that with some e-mails to the maker that show some interest, he might be able to produce a few.

.