Warning - check your fuse box!!!

[Big T]

At the WSR rally, both Salty Monk and I experienced weird electrical problems with our 1978 GS 1000s.

SMs bike would leave the dash panel and other systems hot when the key was turned off. So he checked the fuses and found the main (top) fuse had actually melted the solder on one end and was cockeyed, pushing the main fuse contact down onto the one below. Thus, the phantom dash lights.

Further investigation showed the fuse panel itself had heated up enough to melt the solder on the main power wire (the big red one from the battery). Note that it was just sitting in the hole.

He borrowed a fuse box from Bruce and made it home

My bike lost 2 cylinders while I was passing a log truck on a mountain road. I limped into town and pulled the fuse box open to find the main fuse had slid forward and was barely contacting the right hand clip. I squeezed the clips, reset the fuse and put some tape around the fuses for safety and made it home.

I had recently swapped my original fuse box for a spare one after my bike went dead passing a semi on a mountain highway (bad trend here)

I checked my spare and found the main connector (upper left) to be loose

I finished pulling the box and found it had been resoldered at some point

I noticed the plug had overheated at some point also

I went back to my original one, which does not show any overheating damage. I cleaned the inside of the clips while I was in there.

So, since these bikes have a tendancy to "cook" the electric components, pulling two screws and checking the back of your fuse panel is worth your time.

 

[Steve]

"Cooking" the electrical components is directly related to DIRTY CONNECTIONS.

Clean all your connections, protect them with dielectric grease, you should be good to go for a long time.

.

 

[scrapper]

How hard would it be to replace that style of fuse holder with a newer style fuses holder. Would that solve part of the problem? It seems that something newer would hold up longer?

 

[Big T]

Not necessarily - the best solution is to find out why it's happening and solve the problem.

1. Corrosion at the connectors
2. R/R not working and system overcharging
3. Bad grounds

SMs was especially weird as the fuse solder melted, but the fuse did not "blow"

 

[salty_monk]

My bike also has one of the best & cleanest wiring harness's I've ever seen on a GS... it sat inside since 82 & still has only 28k on it.... I get a good 12v all over the harness & have dielectric on all the connectors.

I think the solder "goes off" (goes brittle) & then the wire maybe moves around a bit & arcs the rest away if that makes sense.

You could very easily change it over to a 4 position blade type fuse box.... ultimately it might be what I do.

Dan

 

[bluewool]

Blade fuses are FAR superior to glass fuses for resisting vibration and corrosion. For the effort involved I'd change the fuse block out. As for the melting a bad connection can generate a lot of heat with out drawing very much current. Think of how hot those old 15w interior lights got in cars, and then you realize that it's only drawing 1.25A at 12 volts!!

 

[salty_monk]

Here we go again... another fusebox 1200 miles later.

As you can see my fusebox is slightly out of position due to the RR sitting next to it:

I am thinking it is probably because it is pulled forward off the plate the wiring can move around a lot more than normal. This one has gone a little quicker & worse plastic deformation than the last one & I can attribute this to the fact this one still has the plastic tag on the red wire so would tend to move around more in the air current.

I believe the solder is "arced" away as the unit moves & touches the fuse below, even the fuse shows signs of getting hot but it didn't blow.

I now have 2 fuse boxes to repair & am going to attempt to find either a solution to the mounting, enclosing the connections in the back with epoxy (should stop the wires being able to move around & re-inforce the plastic base) or switching out to a blade style fuse box.

If I cover the whole back in Epoxy will that cause any issues? I don't believe the epoxy can bridge the circuit & cause a short but I want to be sure....

 

[posplayr]

Here we go again... another fusebox 1200 miles later.

As you can see my fusebox is slightly out of position due to the RR sitting next to it:

I am thinking it is probably because it is pulled forward off the plate the wiring can move around a lot more than normal. This one has gone a little quicker & worse plastic deformation than the last one & I can attribute this to the fact this one still has the plastic tag on the red wire so would tend to move around more in the air current.

I believe the solder is "arced" away as the unit moves & touches the fuse below, even the fuse shows signs of getting hot but it didn't blow.

I now have 2 fuse boxes to repair & am going to attempt to find either a solution to the mounting, enclosing the connections in the back with epoxy (should stop the wires being able to move around & re-inforce the plastic base) or switching out to a blade style fuse box.

If I cover the whole back in Epoxy will that cause any issues? I don't believe the epoxy can bridge the circuit & cause a short but I want to be sure....

I would reflow the solder to all the joints in the back of the fuse box. If you use epoxy you will never get back into it. If you are worried about corrosion you coudl do an acid bath (navel jelly or coca-cola) and then conformally coat it. I would then use something like a hot glue gun to secure the wires. You can always get back in and it is not so sealup that you cant even see the solder joints.

The real problem is that something is getting too hot, maybe that is just the solder getting brittle or maybe not. :|


Note this suggestion

http://en.wikipedia.org/wiki/Soldering

Desoldering and resoldering
Main article: Desoldering
Used solder contains some of the dissolved base metals and is unsuitable for reuse in making new joints. Once the solder's capacity for the base metal has been achieved it will no longer properly bond with the base metal, usually resulting in a brittle cold solder joint with a crystalline appearance.
It is good practice to remove solder from a joint prior to resoldering—desoldering braids or vacuum desoldering equipment (solder suckers) can be used. Desoldering wicks contain plenty of flux that will lift the contamination from the copper trace and any device leads that are present. This will leave a bright, shiny, clean junction to be resoldered.
The lower melting point of solder means it can be melted away from the base metal, leaving it mostly intact, though the outer layer will be "tinned" with solder. Flux will remain which can easily be removed by abrasive or chemical processes. This tinned layer will allow solder to flow into a new joint, resulting in a new joint, as well as making the new solder flow very quickly and easily.

The EZ/ED fuse boxes cant do this. They use a more modern spade type fuse and there are no internal solder joints. You just need to wire into teh connector that plugs into the fuse box.


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Just in case anybody is not familiar with them, you can pop off the bottom (on the back) and the fuse box contains copper/brass(?) conductors bent into shape to form a male spade at the end of the box when the connector plugs in and a female receptical on the other end for the fuze. There is no wire or solder of any kind inside the box. And as it is copper/brass(?) it cleans up nice.

 

[salty_monk]

Looked at those & other alternatives but then you need the connector from the wiring harness of the same bike....

Mine has to be related to movement of that top fuse caused by the red main wire wiggling around. Big T's fusebox was also a little loose on those top clips in the same way...

I think it is a built in problem that is being amplified by my positioning. Maybe the red wire needs to be anchored more firmly so it cannot move around.

My epoxy idea was not related to waterproofing, more to making sure the wires/connectors cannot part company with the plastic body of the fuse box & also serving to re-inforce the fuse box.

I agree that something is getting too hot but my theory is that it only gets too hot when the top fuse drops down onto the lower one. You would then get a short going "on /off" with every little vibration as you ride, wouldn't take long for that to cause the electrical damage. None of the connectors etc show any sign of heat damage (& the RR is not routed through there, it has it's own fuse & goes direct to battery +ve).

Dan

 

[salty_monk]

The fix for me:

Doesn't look pretty but you can't see it with the cover on.....

Having done further testing the fuse is not getting hot so it must have been the movement that caused the initial problem until they could touch & arc & then they got super hot from there & made it 10 times worse.

I also re-flowed all the solder on the back before filling it with the high temp epoxy (Devcon plastic weld).

 

[duaneage]

While crimping may seem inferior to soldering the mechanical connection is impervious to melting at low temperatures. And lest you think crimping is a weak connection, quite a bit of force is exerted on the wire and connector joining the soft metals together.

If you do solder again clean the flux from the joint with alcohol and protect it with clear lacquer. This prevents oxidation or corrosion.

 

[duaneage]

Blade fuses are FAR superior to glass fuses for resisting vibration and corrosion. For the effort involved I'd change the fuse block out. As for the melting a bad connection can generate a lot of heat with out drawing very much current. Think of how hot those old 15w interior lights got in cars, and then you realize that it's only drawing 1.25A at 12 volts!!

I had the glass fuse on my car stereo primary power open up because the solder melted inside the fuse. Intermittent as all get out. I thought my amp was going south.

I replaced it with another glass fuse but made a point of cleaning the connections real good. There was dirt in the socket which heated the fuse and opened the circuit.