Author Topic: Instrument lights not working  (Read 189 times)

Offline Rivan

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Instrument lights not working
« on: April 18, 2021, 08:19:59 AM »
Yesterday I took the 2006 750 Breva out of its shed after its winter lay up. The battery was low, so I charged it one hour or so with a conventional (not trickle) charger. I started it up all working AOK - rode it a short while, parked it up, washed it, let it dry off, then started it up again (after charging the battery with a conventional charger (not trickle) for a further half an hour.

The bike started and ran - but all instrument lights had vanished - everything else working. All fuses OK.

Any suggestions very welcome.

My own theory is that the battery has more or less had it, enough initial current to start and run but insufficient voltage for ancilliary systems (presumably the charging circuit is coming in full blast after starting). I will be fitting a new battery next week.

This is the first time in 15 years of ownership of the machine there has been any sort of electrical fault.

Offline Wayne Orwig

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Re: Instrument lights not working
« Reply #1 on: April 18, 2021, 08:27:55 AM »
If there is enough power in the battery to crank the motor, it will light those tiny bulbs for days.

Relay maybe?
How did you check the fuses?

Double check that the brake light from BOTH switches is working. On many Guzzi's the brake light power is the same as the instrument lights.
And those tiny instrument light bulbs are not known for long life, maybe the just popped.

« Last Edit: April 18, 2021, 09:37:33 AM by Wayne Orwig »
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Offline guzzisteve

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Re: Instrument lights not working
« Reply #2 on: April 18, 2021, 08:36:09 AM »
Hey, Welcome to the madness. It may be that cleaning the pins & connectors on the dash plugin is in order, especially after washing it. Try contact cleaner or DeOxit electrical cleaner.
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Offline Murray

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Re: Instrument lights not working
« Reply #3 on: April 18, 2021, 08:41:47 AM »
Instrument lights as in the baclights for the speedo/tac or instrument lights for the idiot/ warning lights? Does your tail light work? (not to be confused with the brake lights).

Wildgoose Chase Moto Guzzi

Re: Instrument lights not working
« Reply #3 on: April 18, 2021, 08:41:47 AM »

Offline Rivan

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Re: Instrument lights not working
« Reply #4 on: April 18, 2021, 08:46:13 AM »
Thanks for feedback.

Instrumentswork OK - it's all the various warning lights that have gone 'out'. Fuses (all of them) checked OK visually and with a Fluke. Pins A1 clean, no verdigrese.

Noted that although battery takes a charged and will start bike etc, voltage decays inside 3 hours to 10.5v - I believe this fault is due to a low grade battery

Online Kiwi_Roy

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Re: Instrument lights not working
« Reply #5 on: April 18, 2021, 08:51:38 AM »
Here is a schematic
https://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif
The dash seems to be fuse B, may be wrong though.
Fuse B also powers the tail-light and park bulb in the headlight, are those on?
« Last Edit: April 18, 2021, 08:53:26 AM by Kiwi_Roy »
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Online moto-uno

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Re: Instrument lights not working
« Reply #6 on: April 18, 2021, 07:53:41 PM »
  When you say the voltage decays within 3 hours is this while still riding it or after it's sitting for 3 hours ?  Peter

Offline Chuck in Indiana

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Re: Instrument lights not working
« Reply #7 on: April 19, 2021, 06:49:35 AM »
Quote
voltage decays inside 3 hours to 10.5v - I believe this fault is due to a low grade battery

That is either a *dead* battery, or the mother of all parasitic loads.
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