Turn Signal Indicator Light Wiring???

[Peteg]

So I just switched out my turn signal indicator light (Hi-beam & neutral also) to bright LED so I could see them in the Texas sun. I always thought it was a little weird the Valk only having one turn signal indicator light. All my turn signals work fine and the indicator works when signaling right but not left. I assumed I had a loose wire connection until I checked the wiring diagram. As I read the diagram there is no dedicated ground, only a 12v pulse to one side of the bulb for right signal and a pulse to the opposite side for left signal. I checked the wiring diagrams more closely assuming the ground was being made back in the turn signal switch, but based on my reading of the diagram the circuit is made by flowing through the two opposite turn signal lights  to ground. I guess that would work since the indicator light resistance would be significantly higher than the 2 signal lights in parallel,  thus the voltage divider circuit would put the indicator lamp close enough to full operating voltage for the light to work. Am I correct???? If not can someone explain how the circuit works? I'm assuming the reason my led works one way but not the other is polarity related. Thanks in advance for any help with my WTF moment.

[sandy]

When I clear the cobwebs out; I remember that you have to use an incandescent bulb when there's only one indicator. Yes; the polarity issue is the problem.

[mark81]

There is a way to add a couple diodes and a true ground to the indicator to make the led function properly. I'd try to explain it but you're probably better off searching for someone else's description for modification of the circuit.

[Pluggy]

Non-polarized LEDs:

 In the headlight bucket they flash for each direction.  Like having a right and a left in one item.

https://www.ledlight.com/74-led-bulb-wedge-t5-3030-smd-led-12-volt-ac-no-polarity.aspx

or

https://www.ebay.com/itm/224458729093?hash=item3442c86685:g:JlYAAOSwS1hgm1N~

These don't need any changes to the bike wiring to add diodes.  The diodes are mounted along with the LED in the little circuit card.  These flash in both directions (at least it does on my bike).

[Peteg]

Thanks Pluggy. I already ordered the diodes, but as this stuff is so cheap, I'll be ordering the non polarity sensitive bulb you tagged, so I don't need to cut anymore wires. I already cut 5 to install self cancelling turn signals, but no sense cutting 3 more if I don't have to.

[Pluggy]

Thanks Pluggy. I already ordered the diodes, but as this stuff is so cheap, I'll be ordering the non polarity sensitive bulb you tagged, so I don't need to cut anymore wires. I already cut 5 to install self cancelling turn signals, but no sense cutting 3 more if I don't have to.

LED's installed on a Valkyrie will certainly outlast the bike.  Get it the way you want and it is forever.

[f-Stop]

Here's a simple diagram of the Diode Mod...


I used the Kuryakyn Diode Mod Kit. Cost less than $10.  Here it is installed in the headlight housing...


The light blue and orange wires are the indicator bulb wires.  After the install, the orange indicator bulb wire is the "hot" wire and the light blue indicator bulb wire is the ground.  (It doesn't matter which indicator bulb wire is the hot wire or ground wire.)

[Peteg]

Thanks Fstop. I have the diodes on order and that is exactly what I was going to do, but since I was directed to a non polarity sensitive bulb, I decided not to cut the wires. I've got no problem cutting wires, but if there's no need I don't see point in cramming more connections in the head light can.  If I don't like the new bulb, I'll go in with the diodes.

[RonW]

The activated signals uses the opposite side signals as the path to ground. Incadescent bulbs uses up almost all of the electricity that travels to the non-activated side signals such that the left-over electricity isn't sufficient to light up the non-activated signals. Leds don't have the resistance for this. The idiot light is the cross-over point which wasn't a problem when led bulbs weren't used. I've never heard of those led bulbs until puggy mentioned it which is plug & play sure easier than the diode route and gonna put a lot of diode kit vendors out of business.

[Gondul]

Here's a simple diagram of the Diode Mod...

That diagram is from SuperBrightLEDs... great folks out in MO.
Great service and support, I've been buying all my LEDs from them for years.

https://www.superbrightleds.com/metric-bike-diode-kit-motorcycle-diode-kit

[RonW]

I was talking in the earlier post that the activated signals doesn't have its own dedicated ground but instead finds ground through the opposite side signals, but how is it that the activated side bulbs light up and the non-activated signals don't light up with the same electricity flowing through them indiscriminately.

I'm no electronic expert but my theory is that by the time the electricity reaches the opposite side signals, the electricity is reduced to a point that it's not strong enough to light the opposite side signals. The voltage remains 12V but the amperage has been dropped through a series of parallel branches. In parallel branches the voltage remains the same on each branch, but the amperage gets divvied up. It's a amperage divider like a voltage divider on a series circuit. I think.

The idiot light wire monitors the signals via taps on the front turn signal wires. The tap resembles a 90° 'T' in the schematic but if you rearrange the T into a 'U,' it's easy to see that a tap is parallel circuit which divides up the total amps between it's branches.

The amps on any parallel branch is always lower than the total amps.  Below, the idiot light is a branch of parallel circuit B. Parallel circuit B is itself a branch of Parallel circuit A further reducing the amperage.





The left pic. below, includes a mirror image of right signals circuit, the non-activated side signals in this example. The electricity that goes to the non-activated signals through the idiot light is the end product of two parallel circuits. Each parallel circuit diminishes the amperage below the total amps.

The right pic. is the same schematic folded flat so to speak. The current that exited the idiot light runs into still another parallel circuit, X, which further drops the amps to a point there's not sufficient electrons to heat up the bulb's filament on the non-activated side signals hot enough to glow.

[Peteg]

Yes Ron, thankyou that's what I though. I'll try to explain why the opposite signal lights don't light. It's called a simple voltage divider circuit. All these lights, even the LEDs have an operating range. If the voltage is too low, they pass a little current, but they act as a resister and don't light. The indicator lamp is a much lower wattage than the signal lamps, or it is a relatively a much higher resistance at 12 volts and thus limits the circuit amperage. Therefore when we wire the indicator lamp to ground in series through the 2 parallel signal lamps, we may drop 11 volts across the indicator limiting amperage, and 1 volt across the 2 parallel signals. The indicator lights, the signals don't.

I hope that makes sense.

[RonW]

Anybody who's looked at the turn signal schematic would have the same questions. Somebody explained it to me. A clamp ammeter, flasher, and bulbs and wires, would prove or disprove the parallel circuit theory. I've heard that if you park your bike in a totally dark room you might see a faint glow on the non-activated signals.

[RonW]

..... when we wire the indicator lamp to ground in series through the 2 parallel signal lamps, we may drop 11 volts across the indicator limiting amperage, and 1 volt across the 2 parallel signals. The indicator lights, the signals don't.

• I hope that makes sense.

Affirmative. My theory on diminished amps has nothing to do with the non-activated side signals not lighting up this side of apples and oranges. Apparently. Instead of amperage, it's voltage that's behind this.

Right pic, dotted area, the light bulbs and idiot light form a voltage divider (series circuit). The series circuit divides up the 12v between components on the same wire such that the bulbs will never have 12v. Whatever the reduced volts it's below the threshold voltage needed to light up the bulbs.






when we wire the indicator lamp to ground in series

• through the 2 parallel signal lamps,

Took me a while. There's an additional factor that drops the voltage even more.

[Edited]
Below, right pic., the right front & right rear signals form a parallel circuit. In parallel circuits with two equal resistors the equivalent parallel resistance is ½ the resistance of a single resistor. ¼ the total resistance of the 2 bulbs added together in this example.

Meanwhile, the idiot light and the right signals are in series with each other (R1, R2, left pic). In series circuits the device with the larger resistance gets the larger share of 12V. The idiot light has more resistance than the turn signal bulbs. 48 ohms vrs. 7 ohms respectively by my math. Making the signals' share 1/7 of 12V which is too low to light up the signal bulbs. This is of course without the parallel component in the mix.

Again, the parallel circuit does drop the total resistance of the right signals to ¼. [edit] from 7ohms to 1.75ohms. But this only lessens the bulbs' portion of 12V under the series resistance rule where lower resistance allots a component lower voltage share. Moot point though, since the bulbs already don't have enough volts to light up and dropping the voltage even more won't cause the bulbs to light up.

The parallel sub-circuit though obviously a non factor is still something worth noting in this respect. If you removed either the right front bulb or the right rear bulb (bottom pic.), you'd end up with a pure series circuit where the parallel component ceases to exist. However, the lone bulb's share of 12V would remain as it was below the voltage required to light it up despite the new configuration. Nothing has changed which is a good thing otherwise if one of the non-activated side bulbs were to burn out, the remaining bulb would suddenly begin to flash. Not quite 4-way flashing but 3-way flashing etc.