Topic: 1979 CB650 Turn signal issue

[Barneycanoe]

I have a 1979 CB650, substantially restored by me.

Apart from having to replace the rotor and R/R last year, it starts instantly, runs fine, and uses a little bit of oil.

Turn signals work as they are supposed to, front signals function as running lights.

My issue is that the rear signals also are slightly lit when the ignition is on.

As well, the two turn signals indicators on the dash are also slightly lit.

I have been through everything I can think of short of buying a whole new wiring harness and I cannot find a short anywhere, but there must be one in order for these rear signals to be getting some power.

The rears are two-wire signals and I just don't understand how they and the dash indicators are getting some power. The dash indicators flash normally when the signals are on.

I did have to put in a new flasher unit as the old barrel style flasher will not flash the signals (I've tried four of them), which is a pain as I appreciated the stock configuration where you hit the signal switch and the signal immediately lights up, with the other flasher it takes a second or so and then they flash too quickly for my liking.

I know the new bulbs require more current but even when I bought some NOS bulbs the orig flasher would not work.

Anyway, I have searched high and low on the net and have not come across any report of this kind of anomaly.

Hoping the brains here that have seen everything can point me in the right direction.

Thanks

Dave

[newday777]

Howdy Dave
Try cleaning the turn switch.  The contacts get grungy and make contact causing the problem you have. You can start with some shots of electrical contact cleaner in the switch and work the switch multiple times and repete,
 though you may have to take the switch apart to clean it properly.  I've had to do the spray cleaning on multiple goldwings with the same symptoms.

[newday777]

If you haven't opened up a switch to clean them, this is of the start switch but gives an idea what you'll find in them.

[Barneycanoe]

Great idea, thanks! I replaced the switch with another last year as the housing on the original had a crack that was getting larger.

Thanks
Dave

[Barneycanoe]

OK, I took apart the switch, cleaned everything with carb cleaner, there was a bit of grease in there, dried everything reassembled. A bit better but still a slight glow. I had some electric cleaner downstairs in the basement, should have read your first post more slowly. Anyways I can live with it now.

Regards

Dave

[Barneycanoe]

Interesting to note that this is only with the switch in its central position, with the turn signal switch either on a momentary push or all the way over to either side the glow goes out.

Dave

[HondaMan]

This sounds like a poor ground in the rear turn signals. The wire's grounding point inside the turn signal housing is often rusted by now, and this causes the slight drain current thru the flasher to appear as a slight filament glow, which would normally be shunted to ground. i just fixed this on a 1979 650 that came here for oil-all-over-the-engine troubles (bad O-rings and head gasket from a PO Badwrench episode), and the rear turn signals were glowing unless the flasher was active (for turn). The rear mounts and the sockets inside the lenses were all rusty. Cleaning them up and installing new bullet connectors for the ground wires fixed it right up.

[Barneycanoe]

Thanks Hondaman, for the advice. The turn signals were all purchased new in 2017 as the old ones were smashed off or broken. The ground wires have been checked and put into the plug ends with dielectric grease so I don't think that is where the problem is. Of course I have been wrong before.

Dave

[fizzlebottom]

The turn signal circuit isn't complicated, but it does chain several components together. You very well may have replaced the turn signals and confirmed that the direct connections are clean, but that does not mean all upstream connections are clean. You might need to go through and check all subsequent connectors and components in the circuit for rust or corrosion. You might end up having to replace the flasher relay if it is failing in some fashion, but first check all of those connections.

[Barneycanoe]

Sigh. I thought that might be the eventual road I have to take. Maybe I should just order a whole new wiring harness for about $100 USD.

Dave

[fizzlebottom]

Sigh. I thought that might be the eventual road I have to take. Maybe I should just order a whole new wiring harness for about $100 USD.

Dave

I don't think you need to go replacing the entire wiring harness. That's a pretty drastic measure. Just use a multimeter to trace your grounds, and use a little bit of fine sandpaper to clean up the connections. I think it'd take way longer to replace the whole harness.

[HondaMan]

Umm...by chance, is your new flasher unit a 2-terminal electronic one, not the older thermal type?
If so, they will leak a little current when they are not ON in this circuit. In that case, using a 3-terminal flasher might be the solution? You'll have to ground the 3rd terminal yourself. I usually take it to the main harness ground site.

[Barneycanoe]

This could be it. I will let you know, thanks! The CB650 actually has an extra green wire that is not used with the original flasher. I would put that on the ground terminal.

Dave