Need help with a custom kill switch
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
Need help with a custom kill switch
Hi everyone, I have a 93 f150 with a 4.9 in it that I have installed a GPS tracking system that came with a relay to disable the starter. The problem I have is that if my truck is stolen, they will have already started it and this will only work after they shut it off. I would like to use the relay to shut off the fuel system or the fuel injectors, or computer. The relay needs 12 volt to operate and is a always closed relay. Any help on this would be greatly appreciated. I have thought about using it for the fuel pumps but the truck will still run for a short time until the gas runs out of the system. I would like more info on the injector wiring and to be more specific which wire would be the 12 constant power. Thanks
The Southernmost Mod
Joined: Dec 2004
Posts: 6,902
Likes: 20
From: Caracas, Venezuela
With a dead pump the engine will die within seconds, I have not much to add to help you, but if you can kill the pump just do it, another benefit will be having a potentially dangerous thief farther away from you when the truck dies.
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
Thanks for your thoughts, my truck will be stored in another state so a thief being around me is not that big of a concern. With the GPS Tracking system I installed I will be able to monitor the trucks location at all times. I am just trying to find a way to keep it in the general area if they start to drive it away.
Postmaster
Joined: Aug 2005
Posts: 4,728
Likes: 8
From: Cleveland, TN
Put a hidden switch inline with the rollover safety/impact switch and call it a day... No fuel = No run...
Or, remove the fuel pump relay.. I know they can install another one, but how many thieves are gonna be carrying a relay just in case?
The GPS tracker will still be useful if they tow it away!!
Or, remove the fuel pump relay.. I know they can install another one, but how many thieves are gonna be carrying a relay just in case?
The GPS tracker will still be useful if they tow it away!!
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
Does anyone know where to locate the wire under the dash or in the engine compartment for the fuel pump or can I use the fuel tank selector switch?
More Turbo
Joined: Aug 2012
Posts: 510
Likes: 1
Well if you have ever tried to start your truck with the switch unplugged youll know it dosent start. I would say it would be easiest to put a switch on the hot wire, or hook up your kill switch thingy there. Its probably the easiest to get to also.
Trending Topics
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
Yes you are right about the not starting without a switch, however if the relay failed it would not be the easiest place to get to to by pass the relay. I am really trying to find a wire in the engine compartment. But if all else fails I will use the wire from the switch in the dash. I thank you all for your help so far. I am actually thinking about installing two different relays, one for the starter kill and one for the fuel system. All activated by a GPS transmitter.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Postmaster
Joined: Nov 2011
Posts: 3,533
Likes: 17
From: SW Florida
You don't have to open up the dash at all.
Fuel pump inertial cutoff switch is behind the kickpanel in the footwell, right side of cab. Splice into one of those 2 wires (doesn't matter which one) and you'll be all set, and still have easy access if you need to work on it.
It's a black box, recessed red pushbutton on top.
Fuel pump inertial cutoff switch is behind the kickpanel in the footwell, right side of cab. Splice into one of those 2 wires (doesn't matter which one) and you'll be all set, and still have easy access if you need to work on it.
It's a black box, recessed red pushbutton on top.
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
This truck will be stored in another state so I can fly instead of drive, and have a vehicle waiting for me.
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
You don't have to open up the dash at all.
Fuel pump inertial cutoff switch is behind the kickpanel in the footwell, right side of cab. Splice into one of those 2 wires (doesn't matter which one) and you'll be all set, and still have easy access if you need to work on it.
It's a black box, recessed red pushbutton on top.
Fuel pump inertial cutoff switch is behind the kickpanel in the footwell, right side of cab. Splice into one of those 2 wires (doesn't matter which one) and you'll be all set, and still have easy access if you need to work on it.
It's a black box, recessed red pushbutton on top.
Postmaster
Joined: Nov 2011
Posts: 3,533
Likes: 17
From: SW Florida
It's 12V power, but only with the ignition on...
EDIT: wait a minute, what do you mean the relay has to be tied into a wire with a 12V source? For the coil or the contacts?
If that control module requires the relay COIL to be powered with +12V, then it's likely sinking the other side of coil to common (chassis ground) via transistor. You can still use that circuit thru the relay contacts, just be sure of how you wire the control circuit.
Got a schematic for that thing?
EDIT: wait a minute, what do you mean the relay has to be tied into a wire with a 12V source? For the coil or the contacts?
If that control module requires the relay COIL to be powered with +12V, then it's likely sinking the other side of coil to common (chassis ground) via transistor. You can still use that circuit thru the relay contacts, just be sure of how you wire the control circuit.
Got a schematic for that thing?
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
It's 12V power, but only with the ignition on...
EDIT: wait a minute, what do you mean the relay has to be tied into a wire with a 12V source? For the coil or the contacts?
If that control module requires the relay COIL to be powered with +12V, then it's likely sinking the other side of coil to common (chassis ground) via transistor. You can still use that circuit thru the relay contacts, just be sure of how you wire the control circuit.
Got a schematic for that thing?
EDIT: wait a minute, what do you mean the relay has to be tied into a wire with a 12V source? For the coil or the contacts?
If that control module requires the relay COIL to be powered with +12V, then it's likely sinking the other side of coil to common (chassis ground) via transistor. You can still use that circuit thru the relay contacts, just be sure of how you wire the control circuit.
Got a schematic for that thing?
Thread Starter
|
Junior User
Joined: Dec 2006
Posts: 55
Likes: 0
The schematic reads cut the wire from the ignition to the starter relay, connect the blue wire to a 12 volt only while the key is in the start position. Connect the other red lead to the other end of the wire that was cut. So I figure that the 12 volt is coming from the key and going to the relay. The only other wire is a green one that comes from the GPS to disable the relay. Sorry for the lack of a picture I wish I could show one.