R75/5 Electrical Q

[p2squared]

Was doing fine until…

Now, when key's inserted---no warning lights, no start, or horn. But the headlight will come on (if switched on w/key). High & low beam work, but nothing else.

Battery's good, charged, no corrosion on terminals.

Figuring fuse may be? Looking for direction to start in.

Thanks guys,

p2

[Kurt in S.A.]

Could be a fuse. Could be the starter relay.

Kurt in S.A.

[SteveD]

Early /5 didn't have a fuse at all. Are the contacts in the switch good? That oem switch is old now and probably fragile.
http://w6rec.com/duane/bmw//ignkeys/index.htm

I think the /5 wiring looms are still available and not too expensive. As an aside, after all these years if the bike was a keeper it might be a prudent long term purchase.

[Wobbly]

If the bike has sat unused for awhile, OR been washed with any type of soap... it might be a simple matter of corrosion on the brass switch contacts. I would definitely spray the switch mechanism down through the key hole, and from the inside of the headlamp shell with some type of contact cleaner before I jumped in to buying expensive harnesses and other repair parts.

[spo123]

Disconnect the ground first.
Then, spray a small bit of contact cleaner into and underneath the switch board assembly.
Use a tiny pair of hemostats and a bit of "scotch brite pad".....clean away and then "rinse" with wd40 or something.
You MAY also need to "tweak" the contact arm under the switch board, slightly.