Turn Signal Confusion

[afbluewing]

After scouring the forums for the last hour, I'm not sure where to go with this one. All of my lights work great, except my right front turn signal. It simply turns off while the right rear happily blinks on. So obviously the flasher must not be the issue, and the bulb turns right back on when I cancel the turn signal, so it must not be the bulb.

I'm stumped! Unfortunately electronics are not my specialty with stuff like this, so any guidance would be incredibly appreciated.

[Lucien Harpress]

I could be wrong, but I think the fronts are dual-filament. Your running light half may work fine, but the turn signal part could be burnt out.

Pull the bulb maybe? See if you see anything weird.

[redglbx]

Definitely a bad bulb, as Lucien said the fronts are dual filament, one as a running light which is fine and the other used for turn signal which is burned out, change the bulb, use a 1157. Let us know how you do.

[Shadowjack]

Putting a single element bulb in the front will bridge both circuits and make both front and rear lamps work funny, and they won't blink. My own bike has a bad ground in the housing on the exact same position. I had to run a separate ground wire to the brake splitter nut.

[afbluewing]

Thanks for the advice! I think I'll start by swapping the left and right bulbs to see if the problem flips sides!

[Lucien Harpress]

Visually inspect the bulb too. You can usually tell when you've got a busted filament.

[toomanybikes]

if memory serves ... and your bike hasn't been bastardized... honda generally uses solid blue for the RH flasher and blue with white stripe for the RH running light. LH is similar with orange/orange-white

[nicdes]

Hi,
European models do not have the same circuit but I had something similar with mine.
Is your headlight actually fixed to the frame/fork ?
On mine, as the left turn bulb is grounded in the headlight, as long as the headlight is not in contact with the frame/fork, no ground so no front left turn signal.

[Sidecar Bob]

None of the lights on any Honda should be grounded to the frame. Honda provided green wires for every ground connection and that is what they should be connected to. Some models came with turn signals that don't have a ground wire from the lamp base but there should be a large ring lug under the nut that attaches the turn signal's stalk to the bike and has a wire that plugs together with a green wire in the harness.

Note that if you connect anything to "chassis" ground ahead of the steering head the return current path will be through the steering head bearings. Bearings are not designed as current paths so there will be tiny arcs between the bearings and the races, which will cause pitting and premature bearing wear.

[Sidecar Bob]

BTW: I vote for a failed bright filament in the bulb too. If you aren't familiar with them, the drawing below explains how they work.

Putting a single element bulb in the front will bridge both circuits and make both front and rear lamps work funny, and they won't blink.

The indexing pins on a single filament bulb are aligned so that it can go into the base either way but the indexing pins on a dual filament are at different distances from the end of the base (see drawing below) so that it can only be inserted one way. I won't say it isn't possible to install a single filament bulb in a socket intended for a dual filament one because I have seen it done but in every case damage would occur to either one of the pins or the socket.

Dual filament bayonet bulb.gif

[nicdes]

Some models came with turn signals that don't have a ground wire from the lamp base but there should be a large ring lug under the nut that attaches the turn signal's stalk to the bike and has a wire that plugs together with a green wire in the harness.

Hi Bob,
As far as I remember from my caving journey last february , the inside of the headlight case is grounded with the green wire. The left front turn signal light may get its ground from the fork when the headlight case is on its place, linked to the fork.

[Sidecar Bob]

That would be acceptable but only if you connect to the same piece of metal that the green wire is connected to, but it is always better to connect directly to the green wire to ensure a good connection.

[afbluewing]

Turns out it was just a bad connection behind the headlight! I checked the crimp between the light blue wires and they were just barely separated. Thank you all for your help and advice!

[Whiskerfish]

[Lucien Harpress]

That's why I love electrical problems- it's usually something hard to find, and annoyingly minor. Glad you got it sorted!