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FIA Kill Switches


Lewis
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I bought an FIA engine cut off switch off ebay for the 110, like this one, and wired it up as per the diagram that it comes with. After ~2minutes connected but with the key out the 5ohm 11watt resistor that comes with the switch had gotten very hot - it had melted the cable tie that i had used to secure it. Even after 5mins it had barely cooled enough to handle.

Are they supposed to get this hot, and if so how has everyone else mounted them so as not to melt anything else?

Otherwise, have i made an obvious mistake with my electrickery or is it a faulty unit?

Thanks in advance

Lewis :)

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Did you have the engine running, or anything else running??

Jon

No, the engine was off, and when i disconnected the main live there was no spark, indicating that there were no open circuits. however the earth from the resistor did spark when i connected it to ground.

Got the wiring diagram as (almost) seen on the eBay page?

Yep, thats the exact switch in the picture and the diagram that it came with

Lewis :)

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Oh, sorry, bit dim witted today, the diagram is some 60plus miles away and i wont be back there at the workshop until the weekend, I'll have a quick go on paint and see what i can do

Here goes:

gallery_1739_203_1020.jpg

A) Batt +ive (big terminal)

B ) +ive to engine (big terminal)

1) ignition feed

2) +ive to coil

3) Batt +ive

4) Earth through 5ohm 11watt resistor

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My guess is the two big connections on the 10mm studs are the wrong way round.

When the switch is off one of these is connected to the resistor that's connected to earth. The one that connects through to the resistor should be the engine side. Sounds like you have the battery live side connected to the stud that connects to the resistor in the off position, so your battery is discharging through the resistor.

And in response to "Are they supposed to get this hot?" No. They should only take any current when you switch the FIA switch off with the engine running as it dumps any voltage in the system to earth through the resistor.

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Careful with the crayons, I'm banned from using them after last time :ph34r:

I got banned from using wax crayons in me english GCSE lessons because my mate told everyone that i liked to eat them :lol:

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My guess is the two big connections on the 10mm studs are the wrong way round.

When the switch is off one of these is connected to the resistor that's connected to earth. The one that connects through to the resistor should be the engine side. Sounds like you have the battery live side connected to the stud that connects to the resistor in the off position, so your battery is discharging through the resistor.

And in response to "Are they supposed to get this hot?" No. They should only take any current when you switch the FIA switch off with the engine running as it dumps any voltage in the system to earth through the resistor.

Hmm, that sounds likely, i'll give it a try at the weekend. Thanks Mark

I've usually found that the response to any "should it get this hot?" question is a resounding no! :lol:

Lewis :)

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You take the feed to terminal 3 from the dead side of the switch in the off position(to alternator/starter) so any voltage spike from the alternator goes down to earth via the resistor on termonal 4

these contacts should close when the switch is turned off..but check the numbers, the other switch opens with the switch off

If you take the feed from the battery side then that will go to earth via the resistor and get flammin' hot :o

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On a Tdi what does the ignition coil terminal go to? Fuel cut off solinoid?

P.S. Lewis, I have tea all over my key board because of this:

I got banned from using wax crayons in me english GCSE lessons because my mate told everyone that i liked to eat them :lol:
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P.S. Lewis, I have tea all over my key board because of this:
I got banned from using wax crayons in me english GCSE lessons because my mate told everyone that i liked to eat them

Quite what wax crayons were doing in an english GCSE lesson is beyond me :unsure::D

well according to the diagram I posted you have it wired wrong

Thats exactly the diagram that came with mine - I just remembered it wrong when i drew it thats all. But yes - i had wired it wrong - i seem to recall taking the live of the battery side rather than the engine side, oops

Thanks everyone

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at least you didn't have a nice little warming fire afterwards

It was very close though, i was just stopping to go inside for a cuppa after a job well done when i noticed lots of smoke in the cab :rolleyes: , i'm not overly fussed about the car but it was blocked in by a mates 90 and its unlikely i could have gotten it out of the workshop quick enough to stop the fire spreading if it had gotten that far :o then we would have lost a lot more than the 110's dashboard

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