No joy -blowing fuse #1

[FlatSix]

Looks like I get to chase down a short...

Any advice is appreciated of course.

Took the bike out for a ride right before Christmas.  She was running a little rough, just a little...she idled and all and I thought perhaps its bad gas.  Although it hasn't been long in the tank and the tank is only half full.  FYI, new fuel pump and sending unit for the fuel gauge both installed a few months ago.   

I'm thinking if the fuel is getting old, best to just blow it thru the carbs so I head out for a ride on the highway.  Probably not the best choice, feel free to let me know :)  Again, she is running mostly OK, nothing too bad. But then cruising along at maybe 50 on a parkway headed to the highway maybe 5 miles from the shed and bonk!  I lose all my gauges and the bike is running rougher but still running.  The only life on the dash is one red light, which I honestly can't recall if it was the batt light or coolant temp light.  I have a coolant gauge which is pretty reliable and I don't think the bike was in any overheat danger.  But I just can't remember which light came on after I lost all the other gauges.

The bike made it back running and I shut her down in the driveway.  I removed the side covers and started to look around and see if anything looks out of place and nothing does.  I check the fuses and fuse #1 is blown.  I replaced the fuse with a new one, put in the key and immediately blow the fuse again.  Also, starter doesn't turn over...she be dead.

I looked under the seat to check the tank connection, checked wires going to the rear lights, checked all around the battery, alternator, starter and all wires look good and firmly in place.  Next step is to pull the rest of the fairings off (sorta a pain, remind me to get a naked bike next time) and the tank and start poking around with my electrical tester.

Unless y'all have some better insight.

Dave

Funny anecdote:  The wife asks when I got home what happened.  I told her and she says "you seem to have a lot of problems with that bike" and I said, "just sorting it out honey, but they do sell new ones down at the BMW dealer" as she walked away...

Gratuitous pictures attached.

[daveson]

Look at the wiring diagram for components that get power from a green/black wire (therefore from fuse 1) Unfortunately that's a lot. Disconnect as many unimportant ones as you can, brake switches, clutch, heated grips, etc. If the fuse doesn't blow, reconnect one at a time until you get to the one that blows the fuse.

Especially look at areas you worked on recently, unfortunately that's a lot. There's been a case where the foot peg plate squashed a green/black wire when reinstalled for example.

What I'm thinking about the tricky alternator light, it gets power from green/black and earth from the alternator until the bike starts, then it gets power from both sides so the light goes out. You have a short on green/black so the alternator light was getting earth from green/black and power from the alternator, so the light turned on.

[The Mighty Gryphon]

Does the bike have heated grips?  Were you using them?

My K75RT has heated grips.  I had similar problems a couple times until I found that the wire for the right hand heated grip was worn through by throttle action at the end of the handlebar.  It would blow fuse #1 which lit up the alternator light and kill the instrument cluster as well as some other stuff I can't remember.  It took me a while to realize that the grip heaters were running when the fuse blew.

The scary thing to me was that with the alternator light on, I knew that the bike's electrical system was being fed from the battery.  I suspect that you couldn't run the starter because the battery was being run down while you were riding home.

[FlatSix]

Does the bike have heated grips?  Were you using them?

My K75RT has heated grips.  I had similar problems a couple times until I found that the wire for the right hand heated grip was worn through by throttle action at the end of the handlebar.  It would blow fuse #1 which lit up the alternator light and kill the instrument cluster as well as some other stuff I can't remember.  It took me a while to realize that the grip heaters were running when the fuse blew.

The scary thing to me was that with the alternator light on, I knew that the bike's electrical system was being fed from the battery.  I suspect that you couldn't run the starter because the battery was being run down while you were riding home.

I do have heated grips but they are brand new and I wasn't using them intentionally.  Still kinda warm here is south TX.  It is possible the switch on the pad could have been hit and turned them on.  This is a good possibility though.

I do need to check the voltage on the battery.  Could have charged it while it sat for the last week if I was smart.

Look at the wiring diagram for components that get power from a green/black wire (therefore from fuse 1) Unfortunately that's a lot. Disconnect as many unimportant ones as you can, brake switches, clutch, heated grips, etc. If the fuse doesn't blow, reconnect one at a time until you get to the one that blows the fuse.

Especially look at areas you worked on recently, unfortunately that's a lot. There's been a case where the foot peg plate squashed a green/black wire when reinstalled for example.

What I'm thinking about the tricky alternator light, it gets power from green/black and earth from the alternator until the bike starts, then it gets power from both sides so the light goes out. You have a short on green/black so the alternator light was getting earth from green/black and power from the alternator, so the light turned on.

There are indeed a lot of green/black wires!  I am going to go with your plan and start unplugging things.  After I charge the battery if needed.

I was foolishly hoping it was something easy.

More gratuitous photos:

[The Mighty Gryphon]

Before you start messing with the electrical system, charge the battery, replace the fuse and see if the bike works with the grips turned off.  You might also want to loosen the right grip and slide it 1/8" further out on the end of the handlebar.  That's where the damage to the insulation occurs.

It's possible that in the course of installing your new grip heaters you damaged the insulation at the spot where they enter the bars down at the triple clamp.  In any event, you might want to unplug the grip heater switch from the harness.  I doubt there is any real need for heated grips in Texas, and they just roast your palms and let your knuckles freeze anyway.

[daveson]

It might be an easy solution, it often is.

Just a side issue, is that an earth wire that's only a bee's dick away from the starter relay positive wire?

[FlatSix]

It might be an easy solution, it often is.

Just a side issue, is that an earth wire that's only a bee's dick away from the starter relay positive wire?

Yeah, I was hoping that was it when I opened things up but not sure you it could make the connection with the shielding around the wire.  Honestly not sure what those are supposed to connect to.  One is grey and one is brown and grey and seems to come off the special equipment plug? 

Before you start messing with the electrical system, charge the battery, replace the fuse and see if the bike works with the grips turned off.  You might also want to loosen the right grip and slide it 1/8" further out on the end of the handlebar.  That's where the damage to the insulation occurs.

It's possible that in the course of installing your new grip heaters you damaged the insulation at the spot where they enter the bars down at the triple clamp.  In any event, you might want to unplug the grip heater switch from the harness.  I doubt there is any real need for heated grips in Texas, and they just roast your palms and let your knuckles freeze anyway.

I hope you are right.  I did get some new BMW GS Rallye gloves for Christmas so who needs heated grips anyway.

Put her in the shed and plugged in the charger.  Will take another look tomorrow but I already unplugged the heated grip connector 

Thanks for the guidance gents.

Dave

[The Mighty Gryphon]

Keep us posted!

[daveson]

Another thing to unplug for the test could be the bulb monitor unit.

[rbm]

[FlatSix]

That's the non-sanctioned connector at the end of 61122303557 for the plug in electrical connector directly above the coils.  The additional wiring goes directly to two similar connectors, one on the dash pad and one on the fairing.  The one above the coil is where I plug in my trickle charger.

I attempted to turn it over with the heated grips unplugged and same result.  More specifically I reconnected everything except the heated grips, put in a new fuse, tank back on and connected, put in the key and turned it, all still good, lights come on, fan comes on.  Clicked over the red starter switch on the right handlebar from the right most position to the center position and that is when the fuse blew.  Didn't press the start button.

I will pull the BMU next to check it out.  Mine is modified for all LED lights.

Dave

[FlatSix]

No obvious signs of trouble with the BMU.  At least none that I can tell from looking at it and checking out the solder joints.

[rbm]

If the fuse blows when you enable the kill switch, then you're looking for a permanent ground fault on one of the Green/Black wires leading out of Fuse 1 (you know this).  There must be worn insulation that is grounding on the frame somewhere.  It is common to have this problem on the rear brake switch wiring.  I'd be disconnecting all loads on Fues 1 circuits (BMU, connector for special equipment, clutch switch, rear and front brake switches, connector for additional instruments, and heated grips).  Then, take a multi meter and check for continuity to ground on the Green/Black wire for each one of those loads in turn.  Eventually, I suspect you will find a short to ground on one of them.  I'd check for shorts on the harness side of the connector and on the load side of the connector.  Does what I just wrote make sense to you?

Since you have extensive owner modifications to your bike, I'd also be checking those areas as well.  If the photo above is any indication of what's going on in the bike, then the modifications are not the best quality.

[FlatSix]

If the fuse blows when you enable the kill switch, then you're looking for a permanent ground fault on one of the Green/Black wires leading out of Fuse 1 (you know this).  There must be worn insulation that is grounding on the frame somewhere.  It is common to have this problem on the rear brake switch wiring.  I'd be disconnecting all loads on Fues 1 circuits (BMU, connector for special equipment, clutch switch, rear and front brake switches, connector for additional instruments, and heated grips).  Then, take a multi meter and check for continuity to ground on the Green/Black wire for each one of those loads in turn.  Eventually, I suspect you will find a short to ground on one of them.  I'd check for shorts on the harness side of the connector and on the load side of the connector.  Does what I just wrote make sense to you?

Since you have extensive owner modifications to your bike, I'd also be checking those areas as well.  If the photo above is any indication of what's going on in the bike, then the modifications are not the best quality.

Thank you Robert for your advice.  It does make sense.

[FlatSix]

Update:

We have a runner!

Like I said in my first post, I got to chase down a short.  Following the advice from daveson, the Mighty Gryphon and rbm I began isolating different circuits, brake switches, heated grip switch, BMU, etc. and I found that the connector for additional instruments was causing the issue somewhere in that circuit.  Kinda had me confused for a bit as I was unplugging, testing, re-plugging, etc. with my multimeter...was that continuity on that switch?  Was it not on this other plug, etc?  But I stepped away for some peanut M&M's and found the clarity to keep going.  Continuing to test, I found continuity between the green/black and the brown on the fuel gauge plug. 

Ich habe es verstanden!

Then I reconnected every other circuit except for the orange (fuel) and green (coolant temp) gauges.  At least I think that's what each color is.  Put in a new fuse, turned the key and she fired right up like usual.

Thanks so much for all your help guys. 

Now I need to replace the gauge I suppose and looks like the scooter needs a good cleaning.

Dave

[rbm]

Good troubleshooting.   Open the gauge and take a look inside.  Maybe one of the connectors inside the gauge is touching the case.

[The Mighty Gryphon]

Nice work, you found that pretty quick! 

And... dayamm that's a nice looking brick.

[daveson]

Bonus, and that's a super clean brick.

[FlatSix]

Thanks so much for the kind words and support.

Happy New Year!