94 kill switch wire question

MrPerfect2

5 Year Member

Jul 23, 2019

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Washington DC

Dec 11, 2025

#1

• Dec 11, 2025

• #1

I recently got a 94 mustang after years of owning a foxbody . I have the driver seat out and see a bundle of wires running down sill plate side . There is about 20 wires in it . I would like to cut one wire and run it through a toogle switch to prevent the car from starting when key is turned on . any idea which of these wires would be a good candidate for this ? Thank you

 

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Stang337

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Jul 5, 2025

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Dec 11, 2025

#2

• Dec 11, 2025

• #2

Since Ford changed where the starter solenoid is located (on starter now) you'll need to access the wiring coming from the ignition switch. The bundle going down the door sill won't have it. This link shows the wiring diagram to the ignition switch. https://stangnet.com/mustang-forums/threads/ignition-switch-wiring-help-needed.885082/ I would use #33 white/pink for the kill switch, it would act like you either didn't depress the clutch or have it in park depending on AOD or Stick. Use heavier gauge wire to extend the circuit like 16 or 14 and a toggle switch rated at 20amps 120 volt will be fine. Just my 2 cents

 

MrPerfect2

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Jul 23, 2019

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Dec 11, 2025

#3

• Dec 11, 2025

• #3

are there any wires in this 20 wire bundle on sill plate passenger door area that would prevent engine from starting if cut ?

 

MrPerfect2

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Jul 23, 2019

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Dec 11, 2025

#4

• Dec 11, 2025

• #4

Driver side not passenger side

 

MrPerfect2

5 Year Member

Jul 23, 2019

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Washington DC

Dec 12, 2025

#5

• Dec 12, 2025

• #5

I ran a 16 gauge wire to the ground side of the coil and through firewall to a heavy toggle switch in car . Seems to work perfect .

 

WhiteCobra95

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May 2, 2006

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Dec 14, 2025

#6

• Dec 14, 2025

• #6

MrPerfect2 said:

I ran a 16 gauge wire to the ground side of the coil and through firewall to a heavy toggle switch in car . Seems to work perfect .

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Does this mean you're grounding the coil constantly when the switch is thrown or just interrupting the ground / control circuit? Neither is a good plan. If the switch is constantly grounding the coil when it's in kill mode, the coil might over-heat or catch fire if the ignition is left on since it would have 12V to the + side of the coil and a constant ground (infinite dwell time). If it's just opening the ground/control side of the coil, that's a long run for that circuit which is susceptible to noise and runs a good amount of current during dwell. The starter or fuel pump interrupt approach is probably a safer bet to accomplish the same result.

 

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fasterthangas

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Oct 5, 2016

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Phoenix

Jan 10, 2026

#7

• Jan 10, 2026

• #7

Fuel pump power wire. Green/yellow?
You can tap into it in the driver's foot well.