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Headlight and Taillight Fluctuate with Flasher Relay

Discussion in 'Norton Commando Motorcycles (Classic)' started by William Gleason, Mar 30, 2019.

  1. William Gleason

    William Gleason

    Oct 21, 2018
    I am restoring my first - and new to me - 850 Commando Roadster (1973). Finished up wiring and when I turn key switch on to parking key - 1st click to left - everything if fine with headlight and taillight on and steady. When I switch to 3 position - run with no lights- I can hear the flasher relay cycling. When moved to 4 position, where the headlight and taillight are on, both lights start fluctuating with turn signal flasher. This is without the engine running and battery is fully charged (13.3 VDC). Also, the turn signals work fine with the switch handlebar switch. What the heck did I do?
    Last edited: Mar 31, 2019
  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Nov 20, 2004
    Do you mean pilot light as the "headlight" shouldn't be on at 'Parking lights'.

    Sounds like the flasher relay light green/brown [LG/N] could be shorting somewhere.
    Last edited: Mar 30, 2019
  3. Niagara850


    Jul 7, 2010
    Check where the wiring harness bends and separates to the tail on the the back plate by the oil tank. Mine shorted out there. Engine stumbled in time with the short. Fooled around looking for for a couple of weeks blowing several fuses then as a last resort stuck one in wrapped with foil and looked for smoke. Found it ;)
  4. Danno


    Feb 7, 2010
    I had a short inside a turn signal stalk that caused the taillight and other side blinker to flash when the switch was flipped. Not enough to blow a fuse, but enough to confuse me for several days.
  5. tomspro

    tomspro VIP MEMBER

    Jan 25, 2014
  6. William Gleason

    William Gleason

    Oct 21, 2018
    Thanks for all the replies - what a super helpful site. I have narrowed it down to perhaps a short in the right handlebar switch housing. I removed the switch housing and the fluctuating head and taillight stopped - yippee. But now the turn signals have stopped working with the switch. Drilling down and think I am getting close.

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