The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: disco51 on August 08, 2016, 10:49:43 AM
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Have an interesting (to me) electrical problem...
Activating the turn signal from the left hand switch results in both front and back turn signals flashing at the same time. The brake light also flashes as well (although it flashes while the turn signals are not flashing in an alternating fashion).
Checked fuses, wires, etc. Nothing obvious. All bulbs work.
The flasher relay seems to be clicking appropriately.
Any thoughts?
Also seems that the front brake switch may be bad. Brake light always seems to be on except when I unplug this. Back break light works as expected when I unplug the front. Related? Anyone had this problem?
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When weird electrical things happen the first suspect should be a bad earth connection causing the current to seek an alternative earth path.
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The first generation R65's had the main grounding / earthing point for the bikes electrical system on the forward ignition coil mount .
It's prone to cracking and result in odd electrical problems .
A place to start anyways !!
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I reckon that the all lights flashing together gives a few clues.
I would, after checking earths, checking fuse and spraying contact cleaner into the handlebar switch, change out the flasher unit itself - on my 1984 this is a generic 3 pin flasher and just about any cheap one that claims compatibility with "Bosch 3 pin flasher" will work a treat.
To be honest after spending 5 minutes thinkign about how you get all lights flashing together I'm inclined, subject to one thing I will come to below, to suspect the flasher or the switch in that order.
If your bike has, or ever has had, an emergency "hazard" switch fitted I would look long and hard that its wiring as well. likewise if yours was a model than has or had a "beeper" then I'd look at that wiring too.
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Thanks for the suggestions.
Spent a solid hour going through the wiring and checking the grounds. All look good at least to my eye.
I think I'll try changing out the flasher next. Hoping to source one at a local auto parts store as the one from BMW looks to be about $50.
I'll keep you posted.
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I took a look at a wiring diagram for a first gen R65 .
Both rear turn signals, brake and tail light all have a common connection for a ground .
The junction for this, is somewhere between the tail/ brake light and the connector under one of the side covers, don't know which side this is on, I have a second generation R65 and the electrical system is different .
Don't know you're electrical experience, but you can disconnect the connector and then check for continuity, or resistance reading from there to the metal contact that the outer base of light bulb touches .
You can do this for each bulb, possible corrosion, broken solder joint / wire .
The solid brown wire is the ground wire .
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I took a look at a wiring diagram for a first gen R65 .
Both rear turn signals, brake and tail light all have a common connection for a ground .
The junction for this, is somewhere between the tail/ brake light and the connector under one of the side covers, don't know which side this is on,
Under the RHS side cover on Gen.1 machines - also look for the wiring there for the (probably removed) beeper, If those wires managed to cross they would cause the problem described.
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Replaced the flasher - still w/ same problem.
Of note, the Novita Turn Signal Flasher EP36 is a direct fit and only $12. Found one at the local FLAPS.
Checked the main ground on the ignition coil - looked good.
I also stripped back to find the common ground for the brake and tail lights - it's about 4 inches back from the rear light. It also looked ok.
I was not aware that I had a hazard switch, but will take a look.
I'll keep looking...
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I was not aware that I had a hazard switch, but will take a look.
I'll keep looking...
Your bike quite possibly never did - but 79-80 R65s came "pre-wired" so all that was needed was to buy and install the switch (the rectangular "knock out" between the instruments is where it went). You bike would have left the factory with a beeper - most people (including beloved wife) removed them. My RS still beeps when the turn signals are activated and I wonder why it is mandatory. Makes more sense than the headlight always being on
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I'm an idiot.
Final diagnosis - I switched the ground and power wires from the rear turn signals. That was it.
Thanks for all the suggestions... trying to spin this into a positive after spending a good 3-4 hours probing the electrical system. Live and learn. Time for a cold one.
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I'm an idiot.
No you are not!
You thought it through and worked out what you did wrong and fixed it. An approach that will serve you well in being the temporary carer of an old Airhead.