I am reconnecting all the wiring on my LT2 restoration and have an issue with the turn signals.  I have followed the Yamaha service manual wiring diagram for the LT2 to the best of my ability, connecting all color coded wires to their like color.  The issue is that the turn signals are operating opposite of the switch.  When pulling the turn signal switch for the Left turn signal lights, the Right signal lights come   and vice versa for the Right signals.  I checked and rechecked the wiring in the headlight nest and from front to back.  The only thing I'm not certain of are some of the Black ground connections in the headlight nest.  The head light does not come on either when switching the key for the headlight.  Not sure if that's because the engine is not running.  That bulb appears to be good.   A new battery is installed.   What Have I done wrong in regards to the turn signals working backwards??  

Left indicators wire colour is dark brown/chocolate, so make sure that the (black?) wire coming from the left front indicator plugs into the dark brown multi female in the headlight bucket, and the rear one plugs into the dark brown from the main harness.

Right indicators are dark green, so replicate the above for those.

I believe that all indicators earth to the handlebars/frame.

If still no good then, and this is unusual, maybe someone has repaired the insides of the switch and soldered the wires to the wrong terminals. In theory it might be possible to fit the "plate" with the wires the wrong way round, but this would take some bending of the wires to get them to change the original direction they were soldered to, and have been in for the last 50 odd years.

Headlight probably won't work without the engine running and (probably!) key in second click round.

I'll just add that guessing there's an indicating light on the dash or tachometer which probably has wire colors for left & right. Therefore I doubt it would matter if those are cross wired as just come from the bulb center conection or the bulb body as it sits in a rubber fitting,
. But then again if the dark brown from that bulb went to lighter brown which is dc always live after the switch, would that cause grief--i don't know. Their similar colors can be confusing.

Yamaha only uses a two wire indicator bulb in the gauge.  

One wire is connected to right and the other left.  The low wattage bulb gets its power from the side selected by the switch and grounds through the filaments of the inactive turn signals.

Example:  Turn signal switch is switched right, the power is sent to the right signals on the bike and the indicator bulb in the gauge.  The other wire to the indicator bulb goes to the left turn signals on the bike and provides the ground connection for the indicator bulb through the much higher wattage turn signal bulb filaments.  

Thank you for the speedy relies.  The wires from the switch don't quite match my original Yamaha service manual diagram.  Wires from the signal switch are Pink (which could be a faded Red?), Light Brown w/ White stripe, Dark Brown and a Dark Green (but that looks more like a Turquoise, so not sure if it's supposed to be Blue or Green) and there's no Black.  With the color variations I'm not sure if explaining how I got it to work would be of any use.  My service manual diagram only shows a Dark Brown, a Dark Green, and a "dotted line" Black to and from the flasher light switch (again there was no Black wire from the switch) But with your replies and some trial & error/ process of elimination I got the signals operating correctly.  I'm so relieved, Thank you!

I forgot to mention that the service manual has no Brown w/ White stripe wire whatsoever, which added to my confusion.

Well done. 

There should definitely be a brown/white wire in all Yamaha wiring diagrams of that era!

Pink is for the horn and the horn button earths against the switch case/handlebars.

I think you mentioned lights? If so, you should have at least a blue, a green and a yellow wire coming from the switch case as well (sometimes more, depending on the light switch set up).

Addition to my previous post.

I've just looked at the LT2/3 wiring diagram in the combined service manual. Not only could I not see the brown/white wire highlighted, it looks like the colours for the left and right indicator circuits are swapped - no wonder you were confused!  

Congratulations!

I can't remember ever seeing a colorized diagram for the LT2/LT3.   The black and white version shows a dashed line from the flasher unit to the switch and doesn't label the color.  That dashed line represents the brown/white which is power in to the switch from flasher.  

Nice work figuring it out!

P.S.  For future reference, Yamaha was pretty darn good about keeping the wire colors the same among different models in the 1960's to 1970's era.  Brown/white is the standard color for power from the flasher and Pink goes to the horn button for example.  So sometimes looking at diagrams for different models can be very helpful when trying to figure things out.

Yamaha was NOT so good at their diagrams and documentation.  Many omissions (like the brown/white not labeled as you found) and even mistakes like Alan found on the right and left signal colors!  So if something doesn't make sense sometimes looking at the wiring info from other models will reveal the answer.