Noisy flasher relay

[Roadrocket]

Hello

I have a fault somewhere in the electrical system, causing my indicators not to work. Bike is 1985 engined bitsa R80, with a mix in the electrical department. What I experience: I turn on the indicators, but they don't do anything. The voltmeter drops to zero. This is intermittent to top the fun. I have a new turn signal/starter/light contact cluster, but the right turn signal was bad from new (!) but worked if wiggled. This I have lived with for a year or so. When testing the switches I could hear a buzzing shrieking noise from the flasher relay in the headlamp shell. I thought the matter would be solved with a new relay, but now that this is installed, things are just the same. I have checked connections in the headlamp birds nest, but all seems ok. I can get both sides to work, but then after a while, we're back to the noise from the relay (new or old), and the voltage drop. I am at a loss here, so any help greatly appreciated!

Cheers, Otto in Denmark

[Ken in Oklahoma]

Hello

I have a fault somewhere in the electrical system, causing my indicators not to work. Bike is 1985 engined bitsa R80, with a mix in the electrical department. What I experience: I turn on the indicators, but they don't do anything. The voltmeter drops to zero. This is intermittent to top the fun. I have a new turn signal/starter/light contact cluster, but the right turn signal was bad from new (!) but worked if wiggled. This I have lived with for a year or so. When testing the switches I could hear a buzzing shrieking noise from the flasher relay in the headlamp shell. I thought the matter would be solved with a new relay, but now that this is installed, things are just the same. I have checked connections in the headlamp birds nest, but all seems ok. I can get both sides to work, but then after a while, we're back to the noise from the relay (new or old), and the voltage drop. I am at a loss here, so any help greatly appreciated!

Roadrocket, electrical problems can be one of the most vexing, if not the most vexing thing about keeping our 20 and 30 year old motorcycles working. Coupled with that is communication, as in how much do we know and how much do you know about electrical systems. So for myself I would want to know how adept are you with electrical systems? Do you have various electrical diagrams for your bitsa bike that you can relate to and we can relate to? Perhaps, more specifically, are you working from BMW wiring essentially for one model, or are you or is your bitsa wiring invented by somebody other than God and BMW? The reason I'm making a point of this is that really meaningful advice needs to be tailored to the wiring you have. And more importantly, a meaningful fault isolation strategy can be devised.

Without it we are sort of scattershooting. So, having said that I'll do some scatter shooting:

1. Are you working with a stock OEM Bosch made turn signal flasher? This is the kind that if you pop the lid off you see what looks like a transistor radio inside. The Bosch relay has bells and whistles such as monitoring if a bulb element is burned out. You could substitute a known good OEM relay and see if that fixed the problem. If worse comes to worst you can wire in an automotive flasher which is simpler to understand and deal with.

2. Strange electrical systems are often caused by the ground connection(s), not the +12V side of the equation. Many of us have spent way too much time trying to figure out how the wiring could be bad, so as to cause the symptoms we are seeing. In the process we completely have ignored the return path of the current to the negative post of the battery.

3. How clean are your various wiring connectors? Some of these old airheads have pretty ugly connector contacts, not only the single wire connector but also the multiple pin connectors. One of the most troublesome such connector is the on under the tank on the /6 and /7 under tank master cylinder bikes. The master cylinder leaks at some point in its life and the fluid mungs up the connector. Even though you aren't addressing the problem directly you might want to consider going through you electrical connections, brighten them up, and spray or coat the connections with dielectric grease. Think of it as good preventative maintenance, even though your mind is totally focused in fixing the %#%^@%$ turn signal problem.

4. When describing your problems it's almost as if there's no such thing as too much information. Don't focus so tightly on one thing, such as the turn signal relay being the culprit that it's all you talk about. You haven't been doing that, but I'm just saying that your helpers are capable of ignoring any non-pertinent details you may give.

5. If you don't have wiring diagrams at hand, they will be helpful. You can find them somewhere on the internet. If we know which year bike is most pertinent somebody here might be able to come up with a link for you.

Editing: It might also be helpful for us if you can roughly describe your electrical troubleshooting skills and/or experience with automotive electrical issues.

Ken

[Deleted User 62]

Otto, welcome to the forum. Some years had a flasher "warning" buzzer. Does it make the noise intermittently? That's most likely the shrieking noise you hear.

[Roadrocket]

Thanks folks!

I think I understand the basics of the electrical system, and have wired my British bikes, which of course are much more basic, as they are even older than the Beemer. Also I try to keep on top of Mr. Lucas in my MGB. This particular problem is however solved! When I wrote my post, I had another poke at the various connections in the headlamp, and behold! One fuse was very corroded, and did not provide much of a circuit. Fuse changed, problem solved! But a corroded fuse... That was a first. BTW the loom is a stock BMW loom with just a few modifications, I just can't fully make out which one of the diagrams in my Clymers manual that fits best, but the R100CS diagrams are about it.

Otto in Denmark