Baffled x2

Anything related to Vespas... ask tech questions, post helpful info, or just read and learn.
tony172
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So I've got an update, on my mates one I've managed to get the flasher warning light working, by swapping the outer 2wires on the flasher relay. I can't really understand how this works but it tells me that the wiring up front is sound, and she will need to buy a new relay.
It hasn't helped the fuel gauge or low fuel light, but that's the next challenge.
I've not tried swapping the relay wires on my own bike yet.

What's the PRD relay?

Thanks again for the help fellas
tony172
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Ok so I've just looked up the PRD relay and you were right. It has been removed.
Would the wires being fitted the wrong way round on the indicator relay affect the fuel gauge/light in any way? I can see that the grey goes up to feed all of those 3 things but I'm having trouble working out of that's the cause of the remaining problem
firekdp
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Preventative restart device. Used on electric start models to make the starter innoperative when the engine is running.
firekdp
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tony172 wrote: Sat Jun 22, 2019 11:28 am Would the wires being fitted the wrong way round on the indicator relay affect the fuel gauge/light in any way?
Can't see how this would be. And if the relay was faulty, I'd expect the indicators not to work on one side. I take it the indicators are AC?
tony172
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I'm not sure if it would or wouldn't affect the fuel system, but I'm hopeful that maybe I'll get it back working with a working flasher. I'm unsure if it will fix it though. The indicators are AC from the reg, and the flasher relay works front/back rather than side/side from what's on the wiring diagram. The indicators on this bike have been rewired so that the rears are connected to the fronts (I'm guessing the rears stopped working) so they flash in sync. I would have thought that swapping the wires would have stopped them working altogether but they still do.
firekdp
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tony172 wrote: Sat Jun 22, 2019 12:16 pmThe indicators are AC from the reg, and the flasher relay works front/back rather than side/side from what's on the wiring diagram.
Yes that's correct, front/back. not side/side :oops:
If the rears have been wired to the fronts, then that can stop the headset indicator from working.
Changing the wires round may get the light flashing again, but current may then not follow it's intended path.
Try earthing out the white/black wire that goes at the sender. If the fuel light doesn't work then, either the lamp has no power from the grey, the lamp has blown, faulty connection between.
rosscla
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PRD?
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."
tony172
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The PRD is a safety device which stops you killing the starter motor if you accidentally hit the button while the engine is running. According to Google anyhow.
Im working till Thurs so I'll update with more electrical findings at the weekend no doubt.
Thanks for the interest and input so far guys, I appreciate your help
tony172
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So, I've now sorted out my mates scooter by earthing out the fuel sensor plugs as suggested above. This activated the light and the gauge, proving that the sender is at fault. Thanks for that!
Now onto mine 👍
tony172
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Hi guys so I've been out to mine and now have all 4 indicators working, had a break in the engine side panel cable.
Still have no fuel gauge although I've earthed it at the sender plug, and it doesn't move at the Speedo end.
Nor do i have an indicator warning light at the Speedo end.
Everything is wired correctly on mine so I'm wondering if it's the Speedo pcb at fault?
Is there anything else it could be?
I've tried the same as I did on the other scoot- swapping the flasher wires but not a peep.
Is there a way to light up the flasher warning by earthing something like how you test the fuel sender?
Thanks again
Tony
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