Mark III LED turn signal help

dirtymartini

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'75 Commando Mark III. I ordered LED turn signal bulbs and LED flasher from Classic British Spares and now have some weird things going on.
With all four led's in the turn signals I get all four signal light up dimly with either the left or right switch on. With all four incandescent bulbs in the signals work as they should.

Trying to troubleshoot, I removed the rear LEDs and put the original incandescent bulbs back in. Now the signals work correctly in both directions. I tried swapping that pattern front to rear with the same results. It seems like as soon as there are more than two LEDs in the circuit it causes problems. I bought the LED flasher...could it be a bad flasher or a polarity problem? I thought these LEDs were not polarity sensitive.

This really has me scratching my head...
 
Common problem with single warning lamp on turn signals. It is your turn signal warning light. You need a "tweaker" diode to prevent current flowing through warning light to other side of flasher circuits.
Paul Goff sells a tweaker setup on his site, where there is also a simple schematic on how to make your own.

Another option is to use a special type of flasher unit with a third connector to control the warning light directly....links to come...

See this post in another thread for tweaker and special flasher unit links:

 
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Thanks for the replies...I just replaced the t/s indicator lamp at the same time with what I thought was an LED but maybe not.
I'll go pull the wires off of the indicator lamp and see what happens.
 
Thanks for the replies...I just replaced the t/s indicator lamp at the same time with what I thought was an LED but maybe not.
I'll go pull the wires off of the indicator lamp and see what happens.
OK, after I gave that some more thought I knew that pulling the wires off wouldn't work. The console bulb I got for t/s indicator is NOT an LED.
 
I just replaced the t/s indicator lamp at the same time with what I thought was an LED but maybe not.

"If you fit a LED bulb in place of a std. warning light bulb it will only work on one side, left or right not both. You need a Tweaker."
 
"If you fit a LED bulb in place of a std. warning light bulb it will only work on one side, left or right not both. You need a Tweaker."
Got it. Do you know of anywhere in the USA to order one?
 
Testing out posting an image. This is the console bulb I ordered. I'll get a tweaker (or make one) and get these LEDs signals working. I love how much brighter they are. Every little bit helps these days.
Mark III LED turn signal help
 
Got it. Do you know of anywhere in the USA to order one?

The tweaker is just a couple of diodes (and wired according to the bike's polarity).

https://www.accessnorton.com/Norton...ights-remove-repair-replace.26014/post-388413

 

However, if you were to buy a ready-made 'tweaker' then it would need to be for a positive earth/ground electrical system unless your Mk3's electrical system has been converted to negative ground but would only involve reversing the diodes to suit.
 

However, if you were to buy a ready-made 'tweaker' then it would need to be for a positive earth/ground electrical system unless your Mk3's electrical system has been converted to negative ground but would only involve reversing the diodes to suit.
Thanks for the link, I ordered one just now. Yes I am still positive earth on my Mk3.
I also upgraded my membership. This is a fantastic resource. Thanks for everyone's speedy replies.
 
Ok, received my tweaker and started the install. The two leads I ran one to each signal wire, single lead to hot side of indicator bulb, other bulb lead to ground. I had them working and started putting everything back together...tested again and they are not working correctly. Whatever position the indicator switch is in all 4 t/s lights light up but are dim.
I'm getting a drop in voltage across the LED flasher. 12.5 volts incoming, flasher side is dropping to 8.4 volts.

Bad LED flasher? I went back and checked all my connections, all look good.
 
That is what ordered. I ended up ordering from Spark and Paul Goff. Tried them both, same results.

Whatever position the indicator switch is in all 4 t/s lights light up but are dim.

For all four indicators to light up with the switch at either the left or right position seems to indicate the current is crossing over at the warning lamp.
 
Or, with LEDs it could possibly be caused by bad grounds most likely at the rear. Try running a jumper wire from the battery positive terminal or a known good ground and touch the other end to each bulb housing (because the chrome plating on the plastic housing is the ground connection between the bulb holder and stem).
 
Or, with LEDs it could possibly be caused by bad grounds most likely at the rear. Try running a jumper wire from the battery positive terminal or a known good ground and touch the other end to each bulb housing (because the chrome plating on the plastic housing is the ground connection between the bulb holder and stem).
Yes, I've had weird indicator behaviors that resulted from poor grounding at the rear tailight bracket. Note the turn lamps must see good ground through their mounting stems, through the lamp bracket, through the mudguard and its forward end mounting to battery tray. Any paint, powercoat, rust etc in any of those contacts may cause grief. Some folks run a more direct ground line to each of the turn lamp housings and solder to the bulb holders.
 
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