Was out giving her some exercise yesterday, and pulled over to pop in some ear plugs, when the bike died- all the idiot lights went out- no power. Flipped the key back and forth and all good. I headed home. I popped the headlight off, because I have had problems with the key switch before, looked like some of the green leads were loose, pushed them on firmly, spun the fuses- . But alas, that was not it. I pulled off all the turn signals and one of the leads that rests against the tip of the light bulb was bent and touching the metal around the bulb, straightened that. That didn't do it. The power works some of the time, but, when I flick the turn signal all power is lost. I haven't blown any fuses. I did not check the fuse harness mount in the bucket, that is next. Any other suggestions? Would this be a short or an open circuit somewhere? Must be open if I am not frying things. Thanks in advance for your help.
Josh
The first place to check is the Starter Relay, which is under the fuel tank. (I know, I know... it's a pain.) The reason for this may become very clear when you get there. The RED power wire from the battery positive terminal passes through the Starter Relay as part of the starter relay socket. The relay and its socket are really in a BAD location, being located under the front brake master cylinder.
When the front brake m/c leaks, it drips highly caustic brake fluid right onto.... you guessed it.... the Starter Relay and its brass electrical contacts that are part of the relay socket.
As you can see from the diagram, all power for the bike passes through that socket and its connections. If you connect a 12V test light between the RED wire at the ignition switch and a BROWN wire on the multi-color circuit board inside the HL shell, it should light up. (This because RED is "hot" all the time.) If you wiggle the starter relay and the light blinks, flashes or goes out, then a very poor connection at the relay is your issue.
Try that.
At a minimum, the electrics in this area usually need a thorough bath of hot soapy water to clean off years of old brake fluid. When that dries, the Starter Relay itself may need replacing. Replacement Relay Here. Finally, because every electrical item on the bike depends upon that RED to RED connection within the relay socket, I highly suggest you dip the relay prongs into No-Ox-Id electrical connection and anti-oxidation compound.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Certainly looks terribly corroded and dirty. That is certainly a reasonably priced relay! I will clean it up and get a new one on there.
Btw, the turn signal makes an audible click, that I can feel when the key is turned on, also original. Should replace it I think. Do you have an Amazon equivalent for that relay?
Thanks again Wobbly!
Btw, the turn signal makes an audible click, that I can feel when the key is turned on, also original. Should replace it I think. Do you have an Amazon equivalent for that relay?
► "If it ain't broke...." But you can still unplug it and treat the prongs with the No-Ox-Id conductivity compound.
► BTW... Pop the top off that relay and look at the contacts inside.
► The dirt won't hurt you one bit, but that green corrosion will kill an electrical system. You must assume... if its in one place, then it's all over. From now on...
• Whenever you unplug anything electrical you must treat the connector contacts before re-assembly.
• You can start today with the 3-pin Voltage Regulator connector on the RH side of the frame.
• On the next rainy day you can pop off the HL lens and unplug one wire at a time from the multi-color circuit board, treat the connector and plug it back on.
All the best.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
That is exactly what I will do..
Best Regards
• This sounds like a PIA, and it really sort of is... but when your lights are brighter and your horn is louder you'll understand that those actions have very positive consequences. Positive consequences for safety in the form of brighter rear warning lamps and brighter nightime headlamp. Positive consequences for reliability when the battery is able to obtain a higher charge becasue the voltage regulator and alternator wiring is now working as it should.
• Still wondering what the old relay looked like inside.
• And how's the blinker-ignition issue working out ?
All the best.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Here is some more pics., lots of corrosion inside! I have some de-ox and a new relay on the way and will post back in a couple days
Mine was a solid ball of corrosion under the cover !
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
And how is the electrical function now ?
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Works great! Even the signal relay clicking has quieted. The de-ox really cleaned up the female side of the starter relay, too. I have not been able to re-create the symptom.
Thanks again!
Josh
Glad that worked out for you !!
Another place to look is under the Starter Cover. Original BMW battery cables are bad to wick the corrosive acid under the cable jacket, all the way from the battery terminal to the starter motor end. Yeah, like 2 feet away you'll have battery terminal corrosion !! That will also affect your starting and charging functions. ANY visible corrosion at the Starter means the Positive battery cable needs replacing immediately.
Corrosion at one end leads to corrosion at the other. Replace !!
You may, or may not need a new cable, but it's a very good thing to know about and check. No rush. Combine it with other duties when you get ready, like inspecting and sealing the breather system.
And of course, if you do remove the cover... applying No-Ox on the bolt-on cable terminals going to the Starter Motor will help. No-Ox can improve ANY electrical connection.
All the best.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Glad that worked out for you !!
Another place to look is under the Starter Cover. BMW battery cables are bad to wick the corrosive acid under the cable jacket, all the way from the battery terminal to the starter motor end. Yeah, like 2 feet away you'll have battery terminal corrosion !! That can also affect your starting and charging functions. ANY visible corrosion at the Starter means the Positive battery cable needs replacing immediately.
On older cables, corrosion at one end leads to corrosion at both. Replace !
You may, or may not need a new cable, but it's a very good thing to know about and check. No rush. Combine it with other duties when you get ready, like inspecting and sealing the breather system.
And of course, if you do remove the cover... applying No-Ox on the cable terminals going to the Starter Motor will help.
All the best.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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