T500 Flasher Indicator

[Powderfinger]

I am doing a rider restoration on a 73 T500 and the flasher indicator has me scratching my head.

The way I understand the wiring when the key is turned on the orange wire sends power to the flasher relay, the light blue comes out of the relay and goes to the turn signal switch, the switch sends power out to green/right or black/left turn signal wires.

The green and black each branch out to the flasher indicator and those are the only two wires to the indicator.

My question is what grounds that socket and what keeps each signal from feeding to the other one?

It looks like the green wire is grounding the socket and the black is the hot for the light, I can see how I could make it work by adding diodes but I don't understand how it worked stock.

[karl pa]

The turn signals are grounded through the stem to frame,the turn indicator on gauge is not grounded.When the right turn signal is activated,power goes out on the green wire,which goes through turn indicator into black wire of left signals and through left signal bulbs to frame.The turn indicator is a low wattage bulb and limits power to left signals,if you remove the left turn signal bulbs and activate the right turn signals,the right signals will flash but indicator will not.

[jabcb]

Consider case with right turn signals flashing.
1) orange wire powers the flasher relay
2) light blue wire connects flasher relay to turn signal switch
3) light green wire connects turn signal switch to right turn signals
4) right turn signals connect to ground
==> and you get right turn signals flashing

3) But the light green wire also connects to the turn signal indicator bulb
4) black wire connects turn signal indicator bulb to left turn signals
5) left turn signals connect to ground
==> and you get turn signal indicator bulb flashing
==> and you get the left turn signals flashing but there isn’t enough current to see the flash

This causes a problem if you switch to LED turn signals because the LED turn signals use so little power that you will see all of the turn signals flashing.
Diodes are used to prevent this problem.

Wiring diagram for the T500: download/file.php?id=690

[Powderfinger]

Ok, thanks guys. I have the wiring diagram, it just didn't make sense how it worked with a single indicator light.

[Alan H]

The turn signals are grounded through the stem to frame,the turn indicator on gauge is not grounded.When the right turn signal is activated,power goes out on the green wire,which goes through turn indicator into black wire of left signals and through left signal bulbs to frame.The turn indicator is a low wattage bulb and limits power to left signals,if you remove the left turn signal bulbs and activate the right turn signals,the right signals will flash but indicator will not.

Actually, the turn indicator is connected through both left and right side circuits - black and green. When you indicate left, the bulb 'earths' through the right (green) bulb filaments to earth, but as the indicator bulb is a small wattage, there isn't enough current passing to light the main bulbs properly. The small bulb acts as a current limiter and should be 1.7 watt, but most folks fit 3.4 watt bulbs as they are easier available. Remember that a 1.7 watt bulb only uses about 0.125 amps, so the correct 21/23 watt indicator bulbs (together on one side = 42/46 watts) = about 3 amps required, so that little 0.125 amps isn't going to show really.
Similarly when you indicate right, the indicator bulb 'earths' via the filaments of the left (black wire) indicators, but again doesn't allow enough current to pass to light them visibly. If you take the covers off both front indicators then try each side in a DARK garage, you may see a very faint lightup on the opposite side that is actually flashing. If you use LED indicators, the centre console indicator has to have a twin led that allows current to pass either way, depending on which side is flashing, so can be made to work easily with the dual element LED bulb.

Just noticed that jabcb posted similar.

[tz375]

I'm not that smart. I used LED indicators, so I cut into the harness and inserted a pair of diodes to stop the cross feed. I had a pile of diodes that I was using to make up kill switch wiring for Race CDI ignitions.

http://www.sparckmoto.com/Products" onclick="window.open(this.href);return false; half way down the page for $7.00 is the easy way to go.