Turn Signal turns four way flasher? - Triumph Forum: Triumph Rat Motorcycle Forums
» Main Menu

Discussion Forums
 » Twins
 » Tiger
 » General
 » RAT

 » Blogs

Motorcycle.com Links

 » Photo

Motorcycle Forums
» Insurance
» Sponsors
» Our Partners
»ATV Reviews
»Motorcycle Games

Twins Technical Talk Technical Talk for Hinckley Triumph Twins: Bonneville, T100, Speedmaster, America, Thruxton, and Scrambler.
Sponsored by: Long Beach Motorsports

LinkBack Thread Tools Display Modes
Old 03-23-2011, 10:49 PM   #1 (permalink)
New Member
Production 125
Join Date: Sep 2010
Location: BC
Posts: 5
Turn Signal turns four way flasher?

Hey, I installed some new turn signals (British Customs) tonight, tested them as I installed each individually and all seemed to be working fine. I put everything back together and now if i switch the indicator left or right, both come on and flash. This does not make any sense to me. Any thoughts?
bcbonnie is offline   Reply With Quote Quick reply to this message
Sponsored Links
Old 03-24-2011, 01:57 AM   #2 (permalink)
Lifetime Premium
Site Supporter
Main Motorcycle: 2009 Bonneville SE
Forchetto's Avatar
Join Date: Jun 2009
Location: Asturias, Spain
Posts: 16,697
Other Motorcycle: Yamaha XV1100
Extra Motorcycle: Qingqi QM200GY-BA
There are only 4 reasons why all 4 flashers can come on at the same time:

If the "live" side of either the front or rear lamps is shorted or somehow connected to the "live" wire that feeds the other side.

If the warning lamp or its holder are shorted.

A defective or disconnected ground on either the front or rear lamp set.

An internal short in the flasher switch.

My money is on the defective grounding. This is how the flasher circuit is wired:

Forchetto is offline   Reply With Quote Quick reply to this message
Old 03-24-2011, 02:08 AM   #3 (permalink)
Super Moderator
Site Supporter
Main Motorcycle: Custom 955 Speed-Tona
DEcosse's Avatar
Join Date: Feb 2005
Location: Pleasanton CA
Posts: 17,874
It's not poor grounding - these are presumably LED turns I guess?
The reason all 4 come on is because of the OEM indicator lamp - this has much lower resistance relative to the now high resistance LEDs - so appears like a virtual 'short' path to the opposite side.

(The most simple test is to merely unplug your instrument connector plug or pull the lamp - if the turns then work normally, you have your confirmation)

The way the 'normal' idiot light works is:
The main current flows through the incandescent turn signals (Whichever side is selected by switch) to ground;
it also flows to a parallel circuit comprising (the indicator lamp (incandescent) in series with the opposite-side turn signals (incandescent)) to ground

The indicator lamp 'lights' because its resistance is much higher relatively (smaller wattage bulb) than the main turn signal bulb;
so proportionately more voltage is dropped across that indicator lamp than the 'opposite' main signal lamp (actually front & rear lamps in parallel) in series with it ;
so the indicator lights and the main lamp doesn't.
Now - when you install LEDs, they have very high resistance compared to the indicator lamp - so now the applied voltage is dropped over the LED turns as opposed to the indicator
- so both sides flash!
i.e. the indicator is now flashing on the opposite side because the higher voltage component in the opposite path is dropped across the LEDs, rather than the indicator bulb.
Hence the requirement to isolate that potential parallel path with diodes.

This is simplified diagram of how original indicator lamp functioned:

The solution is to do the diode mod for the indicator lamp

(note that on the Twins the negative for the high beam lamp is actually Brown I believe)

DEcosse is online now   Reply With Quote Quick reply to this message
Old 03-25-2011, 11:12 PM   #4 (permalink)
New Member
Production 125
Join Date: Sep 2010
Location: BC
Posts: 5
I think you were right Forchetto. Pulled everything apart, took a little more care insulating the wires. Seems to be working fine now.

Thanks to you both for the insight.
bcbonnie is offline   Reply With Quote Quick reply to this message
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Triumph Forum: Triumph Rat Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter your valid email address, that can receive an automated confirmation message. Otherwise, you won't be able to gain full access.
Email Address:
City and/or country where you live
Main Motorcycle
Your First Name
Please insert your first name


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
turn signal flasher rick littleton Twins Technical Talk 18 04-10-2015 07:00 PM
Turn Signal Flasher Relay ArmyBonnie Twins Technical Talk 22 09-27-2012 06:24 PM
turn signal flasher rick littleton The Welcome Center 1 07-21-2010 10:37 PM
Turn Signal Flasher Don x 3 Trophy 4 09-20-2008 11:17 AM
turn signal flasher help needed robadele Sprint Forum 4 07-24-2006 07:29 PM

Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 02:44 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Motorcycle News, Videos and Reviews
Honda Grom Forum Harley Davidson Forum Honda 600RR Forum Kawasaki Forum Yamaha R6 Forum Yamaha FZ-09 Forum
1199 Panigale Forum Honda Africa Twin Forum Roadglide Forum Honda CBR1000 Forum Vulcan Forum Yamaha R1 Forum Yamaha R3 Forum
Ducati Monster Forum Harley Forums Honda CBR250R Forum ZX10R Forum Star Raider Forum Yamaha Viking Forum
Suzuki GSXR Forum V-Rod Forums Honda Shadow Forum Kawasaki Motorcycle Forum Star Warrior Forum KTM Duke 390 Forum
SV650 Forum BMW S1000RR Forum Honda Fury Forum Kawasaki Versys Forum Drag Racing Forum Ducati 899 Panigale Forum
Suzuki V-Strom BMW K1600 Triumph Forum Victory Forums Sportbikes BMW NineT Forum
Volusia Forum BMW F800 Forum Triumph 675 Forum MV Agusta Forum HD Street Forum Suzuki GW250 Forum
Yamaha Motorcycles Victory Gunner Forum Victory Charger Forum Honda Vultus Forum HD LiveWire Forum Ninja H2 Forum
BMW Scrambler Forum Ducati Scrambler Forum Kawasaki Ninja 250SL Forum

Garage Plus vBulletin Plugins by Drive Thru Online, Inc.