turn signal self cancelling mod.

Yes it is hidden, and it is a 6.8V zener

Yea, that shouldn't be there, it is one of the tachometers I was working on that must have gotten merged into that file when I created the PDF

I think that location is pretty common throughout the early XJ series, and with properly rated components it should be OK. Plus most of the time the bikes are moving, which sends lots of cool air over the electronics under the tank.

Did both of your units exhibit the same failure symptoms?

 

OK thanks for the clarifications. The failure symptoms for my original one were that it has gradually become more and more unreliable at canceling the turn signal, only canceling it occasionally now. So I bought a used one but that doesn't cancel at all! (Leading to my theory that they all fail)
I am considering getting a 'New old stock' one but they are £75 (ouch!!) This might clear up the problem once and for all. If it fixes the issue, great, if not then I know the problem is somewhere else in the switch/wiring and I can sell the unit on. However I have checked this side of things pretty rigorously already.
Anyway thanks so much for your help and I will let you know how I get on in due course. Regards, Steve Plant

 

I'm also having problems with indicators. They were working fine until I left the bike alone for a few weeks, now they won't work at all and I can't find out why. Am I right in saying that the reed switch could be responsible? If so, how are they tested? Is it possible to repair?

 

Do you mean the self cancelling function is not working, or the flashers are not working in the left or right position?

 

The whole of the indicator function is not working. The obvious things like fuses are fine. Does the reed switch have the ability to do this?

 

No, the reed switch it is only used to count wheel rotations for the self cancelling unit.

Do any of the flasher illuminate? Is the bike running? Is it connected to a charger?

The self cancelling unit can disable the flashers and in this case they are not illuminated. Unplugging the self cancelling unit rules this out.

Wires can break on the control switch causing no illumination of the flashers on one or both sides, but in this case if one side illuminates it should flash if all else is well.

Insufficient load can cause no flashing, but they will be illuminated - this can be caused by low voltage, dirty sockets, or incorrect wattage bulbs installed.

The flasher relay normally closed contact can open, and in this case none of the flasher illuminate

 

Thanks for the reply. The indicators were working fine until I left the bike for a few weeks in the garage. when I returned, nothing! With the ignition on but engine stationary the whole indicator system is totally inactive. From what you say it seems that the relay could be the issue. Is it possible to test it? It's 5 pin. Cheers.

 

What bike year and model, a 5 pin would likely be aftermarket if it is an XJ series?

 

It's marked Denso FB257H. 5 pin 6mm flat spade conns. Bike is XJ600 1989. I'll send some pics when I figure out how.

 

So you can pretty much ignore what I said as I had assumed earlier version of XJ. And, I can't help much here as I don't have prints or knowledge on that model

 

This is the bike and the part in question. Thanks for your help so far. let me know if you can direct me to how I can test the unit.

 

So I did find this online, but I still have to guess a bit.



The test they have you do appears to check power to the unit (Br) and then power out (Br/W). This would imply like most flasher relays there is a set of normally closed contacts inside the flasher relay, so that makes sense that both pins should have near 12V. If they do both have 12V, then that would point to an issue with the turn signal switch, which directs that to either the left or right flashers and subsequently placing a load on the relay that causes it to operate at a predetermined rate. It's also possible it's bulbs or wiring, but not as likely with both sides not working with no illumination.

Another easy test would be to disconnect the plug from the flasher relay and apply 12V to the Br/W wire on the plug. Then when the turn signal switch is moved to the left or right the applicable flashers front and rear should both illuminate.

The W/G wire is the self cancelling signal that goes to the reed switch. You should be able to toggle that signal by rotating the front wheel and watching the voltage at that pin - not sure of the value but likely toggling between 12V and zero, but could be a lower number and zero depending on the internal circuit.

 

Got it going again!!!
My first 'melt out' was something of a disaster - heat gun to too high! (see photos) But I was much more successful on my remaining duff flasher canel unit. I found that gentle heat made the potting compound go 'rubbery' and more easily removed but it was still a painstaking process.
Once it was all clear I swapped out all the electrolytic capacitors as they were most 'suspect' but oddly they all tested to spec' one removed!
I checked the zener and that was fine as were the resistors and diodes I could get to - but all to no avail when I re-tested it on the bike (using a power drill on the speedo cable)

Finally I was going to move to the transistors when I noticed what appeared to be two dry-ish solder joints. Re-did these joints and bingo! It now seems to work fine and reliably.
I now just have to figure out how to repackage it for permanent fitting back on the bike. I'm a bit reluctant to re-pot it!!!

As a side line a friend of mine says a modern microprocessor version of this is 'quite easy' . I will let you know if he comes up with the goods!
Regards, Steve P