supercat
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| posted on 19/5/10 at 11:05 AM |
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Is my FIA cut out switch broken?
On the terminals marked 2 I have no volts when the switch is in the on position? I assume this is wrong as power from here should go to the ignition?
The switch itself works as it does cut the battery feed when switched off...
Just wanted to check before I spend £20 plus on a new one....
Cheers,
James
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supercat
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| posted on 19/5/10 at 11:10 AM |
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Ahhh.. think I may have read the diagram wrong... the '2' terminals are just a switch that closes when the key is armed? No actual voltage
there?
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02GF74
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| posted on 19/5/10 at 11:11 AM |
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you have measure volts both sides of the contact? not volts across the contacts but one leat to thecontact, other to the battery negative or chassis
if you cannot reach battery.
these switches have a sprung contact that is pushed by the key when turned, kinda as simpla as it gets, would be most unusual for one to break.
no doubt some racing bods will come along and say these are crap design and break all the time 
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edspurrier
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| posted on 19/5/10 at 12:03 PM |
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One of the sets of terminals is on when the switch is off, and off when the switch is on. that terminal is there to provide an earth via a large
resistor for the alternator output, so the alternator has resistance to spin down against if you shut it off.
Don't forget, if you have a booster pack connected cos the battery's a bit flat, leaving the swithc off will short the battery across your
resistor which will start to smoke. this could be embarassing if done at SVA. Not that I'd know.
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RichieHall
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| posted on 19/5/10 at 12:26 PM |
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Eds got it bang on there, terminal 1 is normally open circuit (with the key in) and provides a return path for the alternator, if you use the kill
switch with the engine running.
Terminal 2 is normally short circuit and energises the ignition coil, in series with the ignition key, start switch, whatever your using.
The image below is from David Cooper's website
Rust is lighter than Carbon Fibre!
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