LED indicator help...

Fast Eddie · May 20, 2020

So, today I fitted some super small, super bright, super expensive Motogadget LED indicators complete with a Motogadget flasher unit to my 1980 T140.

All went well and they flash nicely, and they really are incredibly bright for things so small.

BUT...

On the T140 the indicator warning light has a feed to it from each indicator feed. I’ve never looked at or thought about this before, but, obviously, it links the two circuits right?

So, when I tried everything without the warning light connected, the indicators functioned perfectly. When I connected the warning light ... I had hazard lights, all 4 indicators flashing in unison !

The Motogadget wiring diagram doesn’t help as it doesn’t show any warning light at all.

I’m guessing some diodes are required?

Any help muchly appreciated, provided you talk clearly, and slowly and don’t use any fancy electronicy words...

Mike40M · May 20, 2020

Correct, diodes are the answer. A pair of ordinary 1N4001 will do.

Edit: 1N4001 may be a fancy electronic word. Any small diodes will do.

texasSlick · May 20, 2020

Mike40M said:
Correct, diodes are the answer. A pair of ordinary 1N4001 will do.

Edit: 1N4001 may be a fancy electronic word. Any small diodes will do.

Are you going to let FE guess where and which way to install?

Slick

xbacksideslider · May 20, 2020

Yes, Slick me too. I ‘be divined that LEDs are polarity sensitive and those angry electrical pixies outfox me easily

Mike40M · May 20, 2020

Detailed description. The warning light is connected to left and right indicator lamps. Idea is that when switched on left, current will flow through the warning lamp and will then go via the right lamps and then to ground. The small current through the indicator lamp is so small that right hand lamps will not glow. Works well with filament bulbs.

If clear, slowly progress to next paragraph.

When LEDs are fitted, current through warning lamp is enough for lighting up the other side.

So next will be how to fix it.

Remove the two wires to the indicator lamp. Fit one diode to each wire. Connect the other end of both diodes to one side of the indicator bulb. The other side of the bulb shall be connected to ground. One thing I've not mentioned is which way the diodes should be fitted because that depends on if you have positive or negative ground.

How it works. With left indicators on current flows through "left" diode through warning lamp and to ground. The "right" diode will stop current from flowing to right hand indicators.

Mike40M · May 20, 2020

Ooops. More questions asked while I tried to make an answer.
First remove leads to the warning light and connect one side of it to ground. Start indicators. Touch the other connection of the warning light with one of the two wires from the indicators. When you know which one flashes the warning light, put a diode in between. If the warning light flashes, you've the right direction of the diode. Otherwise reverse the diode. When you know what way to have the diodes, you can make a proper installation. Soldering and insulate instead of just twisting together the wires.

ntst8 · May 20, 2020

Paul Goff sells a “tweaker “ which as far as I can tell is just a pair of diodes all joined up and ready to fit.
I made my own from 1N4004 diodes, the local electronics shop didn’t stock the smaller ones.

Fast Eddie · May 20, 2020

Ok, I’ve had a stiff Gin to settle my nerves since reading all the big words above (well most, I skipped some of them).

Seriously, thanks Mike, that’s almost clear, even to me!

The bike is a negative earth BTW. So I assume I’d put the little fellas with the negative side towards the warning light bulb?

These are the little fellas right?

gortnipper · May 20, 2020

You might be ok with just one diode, before the warning light as I did here for my LED headlight.

LED (2018)

I installed a BPF LED I recently picked up from Walridge, looks the same as the Goff Daylighter unit. + ground. My high beam warning is lit when in low beam goes out on like lazyeye6 but was like that before, swapping the blue/white and blue/green turns out the warning light but high beam...

www.accessnorton.com

I made a jumper with some ends of old wiring harness, and a couple of crimp connectors and some shrink wrap.

gortnipper · May 20, 2020

Fast Eddie said:
Ok, I’ve had a stiff Gin to settle my nerves since reading all the big words above (well most, I skipped some of them).

Seriously, thanks Mike, that’s almost clear, even to me!

The bike is a negative earth BTW. So I assume I’d put the little fellas with the negative side towards the warning light bulb?

These are the little fellas right?

View attachment 16348

Yes, those are them. I think you want the marked end of the diode towards the indicator bulb.

» Easy Electrons – Diodes » JeeLabs

Fast Eddie · May 21, 2020

Ok, dumb question time...

Do these diodes get warm, and do they need air? Or can I put two together and shrink wrap them?

Also, if I’m soldering them in, do I need to worry about soldering heat, or can I cut the tangs very short and solder the wires up close to the diode body ?

ntst8 · May 21, 2020

They seem to be quite robust, mine are heat shrink wrapped and soldering was quite close.
I put a piece of heat shrink over each diode and down each trouser leg, and then second short piece around all to hold the two diodes together. So perhaps the soldering wasnt that close afterall.
There is a pic in the Rewiring with M.Unit thread.

Mike40M · May 21, 2020

Look at any old fashioned printed circuit board. About 5mm between solder and components. So they withstand heat fairly well. Best practice is to bend a diode wire back forming a small U and cut off the end. Then tie the wire in the U. Then solder together. It should look like: diode body - 5/16" free wire - solder - wire where tin has not crept in the wire. When done, push shrimp tube back and heat.
More words on a simple task.

Fast Eddie · May 21, 2020

Seems clear chaps, thank you all.

Just waiting on diodes arriving now.

texasSlick · May 21, 2020

Fast Eddie said:
Ok, dumb question time...

Do these diodes get warm, and do they need air? Or can I put two together and shrink wrap them?

Also, if I’m soldering them in, do I need to worry about soldering heat, or can I cut the tangs very short and solder the wires up close to the diode body ?

They do not get warm in use, especially when used with LED's. So you can bury them in a wiring harness if you so choose.

Slick

Mike40M · May 21, 2020

You can have indicators on always, if you want. Loss in diode is approx. 0.125 W

Fast Eddie · May 21, 2020

Mike40M said:
You can have indicators on always, if you want. Loss in diode is approx. 0.125 W

There‘ll be no need for that... it’s a T140, not a Harley...

batrider · May 21, 2020

An alligator clip works well as a temporary heatsink when soldering. These diodes are pretty bulletproof though.

Fast Eddie · May 26, 2020

Diodes fitted. Indicator warning light now working as it should, thanks all.

Also fitted LED warning light bulbs (need all the help I can get to not forget to cancel the indicators), they’re SO bright ! Well chuffed.

LED indicator help...

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