Turn signal malfunction

[QTreiber]

My rear right turn signal stopped working. The front right turn signal stays on, not flashing. I swapped bulbs and found that all of them work.

The metal parts of the bulb socket are slightly corroded and I will thoroughly clean them.

Here comes the part that confuses me:

I checked the wiring and saw that the dark green wire is grounded with a "ring" to the stem of the turn signal. According to the the wiring diagram in my owner's manual the black wire should be grounded or did I misread this? What am I missing...?

Any help is appreciated!

Greetings from the Front Range,
Armin

[James England]

It is almost certainly an earth problem. The light casing is not grounding, so there's no circuit to make the bulb light up. I wouldn't worry about the colours in the manual. Basically, on your light unit, you'll have one wire which goes to the centre of the bulb holder and another wire which is meant to be grounded. On my bike, someone had put a different light unit on and the wires were a different colour from the circuit diagram.

One other thing.... the rubber bulb holder inside the light unit has a metal blade inside it which is meant to touch the side of the metal part of the bulb (in order to ground it)... the blade is attached to the wire which needs to be grounded. Sometimes, the blade isn't touching the side of the metal part of the bulb... or it's making a poor contact. It needs to be clean, touching the metal side of the bulb firmly and then the wire has to be connected to a paint-free part of the bike frame in order to make a circuit and allow the bulb to lightup.....

[DGXSER]

Not sure what year or model you have, would help if that was in your signiture line.

On all of them I have worked on though, the wire through the center of the stem is the positive wire, it is typically a black wire. It runs up round the fender to a bullet connector. Separate one for each side. Then there is a black wire with a ring on it that goes over the threaded stem as part of the mounting hardware to mount the signal to the bike. This is the ground. That wire runs back round the fender as well to another bullet connector.

Now the color of the wire that the bullet connector your plugging into ought to match the wiring diagrams color code.

[QTreiber]

Thank you very much for the responses!

Sorry for not mentioning my model: my bike is a 1979 XS1100 (Standard).

Armin

[fredintoon]

- - - I checked the wiring and saw that the dark green wire is grounded with a "ring" to the stem of the turn signal. According to the the wiring diagram in my owner's manual the black wire should be grounded or did I misread this? What am I missing...? - - - Armin

Hi Armin,
that ring around the stem should be a ground connection no matter what colour wire is on it but certainly check where the other end goes to.
All black wires should be ground connections.
The dark green wires power the left side flashers.
The dark brown wires power the right side flashers.
On your Standard, the blue wires power the running light filaments in both front signals.
I thing that what you are missing is that a PO ran out of black wire one time and used dark green instead.

[crazy steve]

All black wires should be ground connections.

Need to clarify that a bit...

Yamaha used black wire out of the turn signals as the 12v+ feed and those are not ground wires. These would go to the chocolate and dark green wires in the bike harness.

[QTreiber]

Hi Armin,
The dark green wires power the left side flashers.
The dark brown wires power the right side flashers.
I thing that what you are missing is that a PO ran out of black wire one time and used dark green instead.

My Clymer manual actually shows Dark Green for the right flasher and Brown for the left one for the 1978 and 1979 Standard models.

What confused me is that the ground wire coming from the harness does not go to the ground of the bulb socket, it goes to the bottom contact and the positive lead goes to the ground at the stem of the flasher.
I guess it shouldn't matter as long as the flasher unit is insulated from the rest of the bike.

Thanks again,
Armin

[crazy steve]

What confused me is that the ground wire coming from the harness does not go to the ground of the bulb socket, it goes to the bottom contact and the positive lead goes to the ground at the stem of the flasher.

The turn signals are grounded through the housing; there is no ground wire per se. In the front, no ground wire is needed because the signals are solidly attached to the lower tree. In the rear, because you have that rubber grommet, you need to bond around that and the mounting stem is connected to ground. It will work connected either way as long as the power wire doesn't come into contact with the frame, but it would be best if it was right; that way if any sort of 'stuff' gets to that exposed connection, you're not risking a short and blown fuses... or worse.

[fredintoon]

Need to clarify that a bit...

Yamaha used black wire out of the turn signals as the 12v+ feed and those are not ground wires. These would go to the chocolate and dark green wires in the bike harness.

Hi Steve,
even from the factory? and I'd always blamed the PO for that.
Ah well, I suppose there's a miniscule saving to be made by not "handing" the signals.

[fredintoon]

My Clymer manual actually shows Dark Green for the right flasher and Brown for the left one for the 1978 and 1979 Standard models.

What confused me is that the ground wire coming from the harness does not go to the ground of the bulb socket, it goes to the bottom contact and the positive lead goes to the ground at the stem of the flasher.
I guess it shouldn't matter as long as the flasher unit is insulated from the rest of the bike.

Thanks again,
Armin

Hi Armin,
OK, sorry to have misled you. I looked at my Clymers and it shows that too. WTF they'd swap the wire colours round the other way on the 1980s is a puzzle though.
And on your rear signals the brown or green wire should feed the bulb centre contact and the ring around the lamp housing stem should be wired to ground.
Being hooked up backwards as yours seem to be shouldn't matter in theory but in practice, I reckon it's relying too much on the lamp housing being perfectly insulated from the bike frame.

[QTreiber]

If all else fails...

After cleaning cable connectors without success I started systematically narrowing things down with a continuity tester and finally found that part of the outer part of the bulb socket was corroded and did not allow the bracket to make good contact.


Shiny bracket:




Not so shiny metal hidden under the rubber sleeve.



After removing the corrosion with a small wire wheel the turn signal works again, even when the engine is not running.

Thanks again for all your help!

Armin

[natemoen]

That's odd. My 78 has a grounding dost the stocks up from the socket and the strap is just to hold the socket in place.

Glad they work now!