Topic: mystery indicator wiring issue

[NickD]

hi all, so here are the facts:

-1972 CB500 four
-LED motogadget m-blaze bar-end indicators front + generic turn/tail-light strip rear
-stock turn signals work, with the stock bimetal flasher relay
-stock turn signals work with a new, solid-state style flasher relay
-either pair of LEDs (front or rear) work when wired in parallel with a pair of stock lamps
-LEDs, when wired front and rear with no added load do not work. When the blinker switch is engaged, on either side, all four signals light up, dimly, while the "dash" light does not come on.
-when wired up on the bench, the flasher circuit works with the LEDs!

-I've done some basic troubleshooting- grounds all seem ok, tried a few different (all solid state) relays, bypassed the switch on the handlebar, and disconnected the "dash" lights.
Help!!!!
many thanks as always,
-Nick

[calj737]

When both sides light up, and all 4 corners with the activation of the turn switch, it generally points to a "bleed over" condition. Meaning, the current from L passes thru the idiot light and energizes the R side as well. Installing inline diodes on the TURN circuits before the idiot light solves that problem.

You haven't mentioned what gauge or idiot lights you're using either. So without that, can't be sure of how its wired.

[bryanj]

You need to disconnect the indicator repeater when using led

[NickD]

Thanks guys. No gauges. As for the idiot light/ turn signal repeater, that’s what I meant by “dash light.” Disconnecting it yields no change. Is there somewhere else such a bleedover might exist?

[Bodi]

The flasher gets key-on battery power, its output goes directly to the switchpod. The switchpod connects the flasher wire to either side's signal lamps. The indicator, if it's a single bulb rather than one for each direction, connects across the two signal light side wires and the tiny indicator lights from the lit side power and grounds through the unlit side's bulbs. Dual indicators connect to each side's signal power. A single indicator will not work properly with LED signals as-is, some wiring changes are needed.
So there aren't many places L and R signal power can cross. The switchpod is suspect but if all is OK with standard bulbs then it should be OK. Past the pod wiring, the signal wiring just connects directly to the front and rear sockets (and indicator/indicators).
The LEDs being dim is weird as well, I don't know what would make them get a lower voltage... except, again, the switchpod internals.
Can you run a jumper from the flasher output directly to each of the signal wires one at a time? Blue and orange if I recall correctly... these connect to the switchpod, probably under the tank. Connect to the harness end, not the switchpod end. If the signals flash as desired, then I think the problem is in the switchpod?

[bryanj]

Reason i said repeater is that i just had the problem with a mates special where all 4 flashed at the same time and that was because the repeater is wired across both sides so back feeds.
Your problem sounds more like a grounding problem OR some leds are polarity sensitive where others are not

[NickD]

Thanks for all the info guys. I think we've got it. As many of you suspected, the repeater did have something to do with it. What was confusing me was why it didn't seem to help when I disconnected that circuit entirely. Here's what was leading me astray:

- I had tested my relay/ turn signal circuitry on the bench with a set of cheap ebay LED turn signals. I bought these a while back, hoping I could avoid selling an organ to buy the Motogadgets. This circuit worked, but alas, in this case it seems you get what you pay for. The light was pretty weak, and I ended up springing for the fancy German kit.

-I never tested the Motogadgets on the bench, before today

-The Motogadget indicators exhibited the same problem on the bench as they did on the bike. Dim, no flash. It seems they draw less current than the cheapos, and for some reason (any EEs out there?) the flasher relay (even though it's solid-state) didn't like it. Wiring even the smallest of incandescent bulbs (like the ones in our gauges or repeater lights) in parallel with the LEDs solves the problem.

In summary, the problem was ultimately two-sided. The relay wasn't cooperating with the indicators by themselves (no repeater), but the circuit was also flawed with the repeater circuit in place, for the reasons a few of you have mentioned. I've temporarily skirted around the problem (until I order a couple of diodes) by hooking the high beam repeater bulb up in parallel with the right turn signal, and the normal turn signal repeater bulb in parallel with the left.

Again, thanks all for the input. Super helpful when the gears grind to a halt and you've stared at the same wiring diagram a few too many times. 

[bryanj]

Feels good when you sort it