2002 R1150GS Blowing Fuse 5

[robc76]

Good afternoon everyone,
It's been a while since I last posted here and I've had to create a new account. I was previously a member registered as RobC. The reason I've not posted for such a long time is my 2002 GS has been in semi-retirement and has remained reliable. That is until I had just completed preparing it for a 2,500 trip to the Pyrenees.

Two weeks before the trip I had fitted new tyres and brakes and, as it was a nice sunny afternoon, I decided to go for a little ride to bed them in. The bike started as normal but then cut out after 30 seconds or so (however long it took me to close the garage door) and has never started since. I discovered fuse 5 (Motronic) was blown and would blow instantly every time I turn on the ignition. Long story short, I've got the tank off and I've unplugged all of the block connectors. I think the cause of the problem is the right hand switch gear as whenever its block connector is plugged in, regardless of whether the others are or not, fuse 5 blows. I suppose my question is this: Is it likely to be the switch gear? The wiring looks to be ok so the issue may be inside the switch. Or is the problem between the block connector and the various components the switch gear controls (ABS, lights, indicator, starter and kill switch). I think I've ruled out heated grips as they have a separate connector coming from the switch gear and the fuse blows when this is not connected.

Motorworks may have a switch in stock but before I shell out the £105 I just wanted to ask if I am, indeed, barking up the correct tree.

Regards

RobC

 

[Ian J Hartley]

Put the bike in gear with the side stand down and see if the fuse blows When you turn on the ignition.

if it does, then the fault is likely to be wiring to diagnostic connector or motronic.

if it doesn’t then pull the motronic relay and substitute it with the horn relay.

Put the bike in neutral and side stand up.

Does the fuse blow now when you turn on the ignition

if it doesn’t then likely faulty relay.

if it does then it could be the Rider information display or motronic.
Try unplugging the Rider information display. 8 way grey coloured connector at the headstock and check again.

let us know what you find.

 

[Steptoe]

Put the bike in gear with the side stand down and see if the fuse blows When you turn on the ignition.

if it does, then the fault is likely to be wiring to diagnostic connector or motronic.

if it doesn’t then pull the motronic relay and substitute it with the horn relay.

Put the bike in neutral and side stand up.

Does the fuse blow now when you turn on the ignition

if it doesn’t then likely faulty relay.

if it does then it could be the Rider information display or motronic.
Try unplugging the Rider information display. 8 way grey coloured connector at the headstock and check again.

let us know what you find.

I always enjoy reading Ian’s succinct and very accurate electrical diagnostic advice.

 

[robc76]

Thanks Ian, this is just the sort of reply I was looking for - I don't like firing the parts cannon. I'll run the tests tonight - I'm glad I bought a 30 pack of fuses

Regards

RobC

 

[MikeO]

The main loom on the 1150 passes under the battery holder, on the left side of the bike. The rubber mounts on the battery cage allow enough movement over time for the bottom of the cage to chafe on the loom. Eventually it will cause a problem (mine was the fuel pump circuit) - repaired and a bit of flexible chopping board stuffed between the loom and the box sorted it out.

 

[robc76]

Put the bike in gear with the side stand down and see if the fuse blows When you turn on the ignition.

if it does, then the fault is likely to be wiring to diagnostic connector or motronic.

if it doesn’t then pull the motronic relay and substitute it with the horn relay.

Put the bike in neutral and side stand up.

Does the fuse blow now when you turn on the ignition

if it doesn’t then likely faulty relay.

if it does then it could be the Rider information display or motronic.
Try unplugging the Rider information display. 8 way grey coloured connector at the headstock and check again.

let us know what you find.

Bike in gear, side stand down - fuse does not blow.

Bike in neutral, side stand up, horn and motronic relays swapped - fuse blows.

Bike in neutral, side stand up, RID connector unplugged (the most awkward one of the lot) - fuse blows.

At no point did the RID show anything. It was working as normal when the bike last ran.


I have not checked the wiring from the connector to the RID nor anything from the connector blocks backward so if the battery tray is chaffing the loom I've yet to discover it.

RobC

 

[Ian J Hartley]

The only other thing to try and unplug is the Motronic itself.

If the fuse doesn’t blow with the motronic unplugged, then it points to the motronic being at fault.

if the fuse still blows, then you are looking for a short somewhere on the wiring loom green/black wire.

As Mike O suggests, a good place would be under the battery tray.

 

[Ian J Hartley]

The Right hand switch gear is allowing the Motronic relay to be powered, hence why the fuse keeps blowing.
Your problem is down stream of the Relay on the green/black wire which only feeds two components, your RID and the Motronic.

so we know it’s not the relay and the RID, so if unplugging the motronic and the fuse still blows, then all that is left is the green/black wire it’s self.

Pin 6 of the RID connector is the Green/black wire and a continuity test between it and ground should be open circuit, so if after unplugging the motronic the fuse still blows. Then setting up a continuity test at that point whilst flexing the wiring loom might help pin point where any fault might lay.

 

[robc76]

The only other thing to try and unplug is the Motronic itself.

If the fuse doesn’t blow with the motronic unplugged, then it points to the motronic being at fault.

if the fuse still blows, then you are looking for a short somewhere on the wiring loom green/black wire.

As Mike O suggests, a good place would be under the battery tray.

Thanks. I'm sure I unplugged the Motronic unit the other day and the fuse did not blow but I cannot remember what else I had disconnected at the time. I'll give it another shot tonight. It doesn't sound wrong for the Motronic to be the problem as it is pretty crusty here and there so it is possible there has been some water ingress. Motorworks may have a used unit in stock and it is cheaper than the switch gear at only £95.

Rob C

 

[Ian J Hartley]

When you have it all back together, and if you can confirm it is the Motronic unit that is blowing the fuse, then there are a few other things to consider:-

The motronic unit does provide power to a few of the input devices such as HES and Throttle potentiometer, but its internal protection circuits should protect it from these items malfunctioning. So it’s worth a try just in case to go around disconnecting each of these in turn. All the other devices such as Lambda probe, HT coil, fuel injectors have separate power supplies and are triggered by switched earths from the motronic, So these are extremely unlikely to be dragging the main power down enough to blow the fuse. The Air Temp sensor and Oil temp sensors are just variable resistance values for the motronic. Still as all these other devices provide relatively easy access to their connectors, it would do no harm in trying unplugging each in turn.

 

[Grizzly]

Hi RobC
It could well be an earth fault on the cable and plug which is stashed on the right hand side in line with front of pillion seat - in a recess in undertray - it's only used in certain markets - California? and in all other markets it just lies about until it eventually rubs on a frame web etc.
It's a Motronic output so gets supplied with 12V+ as soon as ignition is switch on - I would suggest you hunt it out and check before doing anything else.
If I remember correctly it's described as Timing Valve on BMW wiring diagrams.

Cheers.................................Grizzly

 

[Ian J Hartley]

Hi RobC
It could well be an earth fault on the cable and plug which is stashed on the right hand side in line with front of pillion seat - in a recess in undertray - it's only used in certain markets - California? and in all other markets it just lies about until it eventually rubs on a frame web etc.
It's a Motronic output so gets supplied with 12V+ as soon as ignition is switch on - I would suggest you hunt it out and check before doing anything else.
If I remember correctly it's described as Timing Valve on BMW wiring diagrams.

Cheers.................................Grizzly

No it’s not!

The connector you highlight is a power output from the fuel pump relay and shares the same power as the fuel pump, fuel injectors, lambda probe and has nothing to do with this fault.

 

[Grizzly]

Oh well! It was a long time ago! - must have been fuse 6 blowing. My apologies for any confusion caused.

Cheers......................Grizzly

 

[robc76]

Update:
I plugged everything back together then removed the Motronic unit. Fuse still blows.
I had to google how to do a continuity test on the RID green/black wire so I don't know if I did it right. This what I did:
- removed the battery in case I need to remove the tray later;
- Plugged everything back in including the Motronic unit;
- Put the red probe of my multimeter on the RID green/black pin and the black probe on the battery negative cable.

The result is the multimeter reading varying wildly from 100 to over 1000. I never saw it get close to 0. Did I run this check correctly?

RobC

 

[Ian J Hartley]

Not sure exactly what it is you are doing.

It looks like you may have a short somewhere along the green/black wire.

So what I would do is.
Disconnect the RID and the Motronic and remove the Motronic Relay.
This will isolate the green/black wire.
Measure the resistance between Green/black wire at the wiring loom RID connector and ground or battery negative.
It should show open circuit.
If not then it indicates a problem alone the wire somewhere.
(your values 100 to 1000 ohms points to a short to ground somewhere)
All you have to do is whilst leaving the multimeter connected, monitor it whilst you flex the cable looms from the motronic and RID connectors back towards the fuse box.
All being well, at some point the multimeter should show open circuit.
when it does it will point to the area of the cable loom which needs further investigation.

 

[robc76]

Not sure exactly what it is you are doing.

It looks like you may have a short somewhere along the green/black wire.

So what I would do is.
Disconnect the RID and the Motronic and remove the Motronic Relay.
This will isolate the green/black wire.
Measure the resistance between Green/black wire at the wiring loom RID connector and ground or battery negative.
It should show open circuit.
If not then it indicates a problem alone the wire somewhere.
(your values 100 to 1000 ohms points to a short to ground somewhere)
All you have to do is whilst leaving the multimeter connected, monitor it whilst you flex the cable looms from the motronic and RID connectors back towards the fuse box.
All being well, at some point the multimeter should show open circuit.
when it does it will point to the area of the cable loom which needs further investigation.

Thanks Ian. I thought it logical to have everything except the RID plugged in to have a full circuit to test. This here is an example of why forums such as this are a valuable resource. I will do as you suggest this evening.

RobC

 

[Ian J Hartley]

The RID and the Motronic have electrical components inside which will always give false readings when doing continuity checks, which is why it’s good practice to disconnect them.

 

[robc76]

Update:
Motronic unit, relay and RID disconnected. Resistance of the green/black wire between the RID connector and the negative battery cable is high. The resistance varies between around 30 and 1200 ohms depending on how I wiggle the main loom.
I have removed the loom wrapping from the RID connector back to the main loom and then as far back as I can before it disappears under the ABS unit. There is an accessible section of the loom into which a lot of wires go and are then spliced into more which then go into the part of the loom that goes under the ABS unit. The RID green/black wire is one of these. It is spliced into two, larger, green/black wires. One goes to the Motronic connector and the other somewhere under the ABS unit.
As far as I can see, all three green/black wires look ok (hard to get close enough to be certain) so it looks like I need to remove the ABS unit to investigate further. The Haynes manual doesn't say how to do this and it looks like an involved job so I may have reached my limit here - unless removing the ABS unit is actually very easy.

I'll spend another hour or so probably poking around just in case I"be missed a piece of split insulation.

RobC

 

[Ian J Hartley]

Those resistance values clearly indicate there is a fault somewhere along the green/black wire. Have you looked at the RID connector housing for corrosion on the connectors. it’s exposed to the elements so nearly all the connectors on the headstock which aren’t weather protected are at risk of corrosion.

You are progressing towards the Battery tray where the main loom passes under towards the Fuse/Relay box.

This is the Green/Black wiring isolated from the main loom for reference.

 

[robc76]

Found it. Chaffed by the battery tray. I'd post a photo but I can't find the option to do so.

I can get continuity between the RID connector and the bare wire and also from the wire to the relay socket. I also get continuity from the RID connector to the relay socket. However, I no longer get continuity between the RID connector and the battery negative cable but I have unplugged a few more things to get access - alternator, ABS pump and something else I cannot identify yet.

Anyway, I'll tape up the bare wire and plug everything back together and see what happens.

RobC