ELECTRICS: Mysterious "Earthing" Problem?

[daPEEG]

Hi all,

It's been a few years since I've posted on the forum - I need some of your sage advice please...

There seems to be a "Short" or "bad Earth" somewhere that have the same components in common - they randomly all shut down together.

Has anyone else had this problem?

The Indicator lights(Flashers); Hazard Lights; Headlights; Tail lights and Horn all erratically switch off at the same time.

The problem seems to be very random, Sometimes when I switch on the ignition all these functions are working but most of the time when the ignition is turned on, they are NOT functioning.
Other times I will just switch something on and all of these will suddenly go off.

I discovered that when I activate the "horn' switch, it sometimes "self-repairs"? I suspected a bad wire in the handlebar switch cluster and disassembled, cleaned and re-assembled it - to no avail, the problem persists.

I suspect a bad earth in one of the wiring looms (because on the wiring schematic, these components are all common to ONE SPECIFIC LOOM).

I am NO ELECTRICAL EXPERT and need your advice PLEASE !
I need to know 'where' and 'how' to start tracing this fault.

I'm planning to take my 2002 BMW R1150GSA (Heeler Sidecar) on the International DGR (Distinguished Gentleman's Ride) later this month and need to get this problem sorted out.

I'm in Johannesburg - South Africa

 

[topcat2006]

I would check the plug where the switch assembly plugs into the main loom. Both sides. Split it, clean the contact and reassemble. I'd also check the frame earth points. Take them off, clean them and reassemble. I'm pretty sure it's a tank off job.

 

[daPEEG]

Thanks, I have the tank off. I'm about to start opening up the loom for the inspection...

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[Steptoe]

There’s a single main earth point in the instrument loom that’s prone to turning to green mush. You don’t need to remove the tank to check it.You need to cut the outer sheathing on the main instrument loom approx where it’s attached to the front fairing frame, behind the oil cooler, the lowest point in the loom and where the water gathers and rather unfortunately where the earth points are all joined/crimped together unprotected . It could also be a broken wire in the ignition loom, have you tried wriggling the ignition loom wiring around to see if the problem goes on and off ?

 

[daPEEG]

There’s a single main earth point in the instrument loom that’s prone to turning to green mush. You don’t need to remove the tank to check it.You need to cut the outer sheathing on the main instrument loom approx where it’s attached to the front fairing frame, behind the oil cooler, the lowest point in the loom and where the water gathers and rather unfortunately where the earth points are all joined/crimped together unprotected . It could also be a broken wire in the ignition loom, have you tried wriggling the ignition loom wiring around to see if the problem goes on and off ?

Yes, I'm going to check that loom as well as the one leading to the ignition switch. I've got a LOT of work ahead of me...

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