Old school “security” mod:
Starter kill and fuel pump kill switches.
A person wanting to drive my car would have to know to push the starter kill button while turning the key. Also, they would need to know to switch the fuel pump on. These two mods in addition to the OEM Scion Security system make it difficult to steal the car. Effectively, to steal my car you’d have to tow it.
These are the momentary switches I use
Starter Kill Described
The way it works:
- Tap into the 12v power wire that triggers on when you turn the key to start the car.
- NOT the 1st stage AC power wire.
- The actual full turn to crank your car is a different wire, this is the wire you tap.
- To start the car you must simultaneously push a momentary button, and then turn the key (fully) to start the car. Release both after car starts.
- What you’re doing is completing the 12v circuit to the wire by pushing the momentary button and that allows the car to start when you turn the key.
- Push the momentary button, that triggers a 4-pin relay.
- The relay then completes the 12v power to the starter wire.
- Turn the key (fully) to start the car
- After the car starts, release both the button and key at the same time
Another (more simple) way to accomplish this would be a hidden 2-prong toggle switch that just cuts off the 12v power to the ignition wire.
Starter Kill wiring with relay
These instructions serve as a general guide. Please make sure to do all your testing with a multi meter first. That said, the wiring below is exactly how I have it on my 2006 Scion tC. There could be differences in other years so do your research and test with your own multi meter first.
This is the actual wire to tap
Open up your steering column covers and find this harness under the key lock cylinder. The wire shown below (red arrow) is the wire you’re tapping. I recommend you test with a multi-meter first to confirm.
Fuel pump Kill switch
Plain and simple: Switch the fuel pump OFF, engine will not get gasoline, car will go nowhere. Keep in mind this is always on. For this switch I use a marine grade heavy amp rated, two-prong toggle switch, directly in line to the fuel pump 12v power wire. This is a simple way of installing it.
The downside is if one were to accidentally bump the switch it would kill the fuel (even while driving). Also you need a switch that is rated high enough to withstand always being ON, it should be capable of supporting enough amperage if your fuel pump is working hard (example carrying load, accelerating hard, etc). A typical fuel pump for a normally aspirated 4-cylinder engine will draw 4-10amps at most.
The more fail safe way to wire this would be with a 5-pin relay such that toggle in the OFF (at rest) position sends the 12v power, but when switched ON it kills the fuel pump. This way, if the switch fails, the relay is still at rest, enabling 12v power to the fuel pump.
-
Single pole, single Throw toggle switch turns one circuit on and off. PVC coated for water resistant integrity
-
Nominal voltage is 12V. Rated for 25 amps at 12V DC
Wiring the Fuel Pump Kill switch
For obvious security reasons, no pictures of my install location for this part.
-
Take the back seat out
-
Interrupt that wire, extend it to the switch prongs (route it under the carpet as needed)
-
Use the switch to complete the 12v power circuit to your fuel pump
-
After testing, hide the switch where nobody will see it, and you won’t bump into it on accident.
-
ADVICE: I would use the same gauge wire as the fuel pump power wire AND soldered connections.
Links to soldering tools and accessories
-
Adjustable heat soldering tool kit complete with extra tips, solder, flux, etc. You can use this for the DIY Cluster LED swap too, very handy to have
-
Butt connectors that melt solder to the connections, I really like these
-
Heat gun with melting shield, great for melting the butt connectors above. You can get in tight spots without heating up neighboring parts
-
Tube shrink wrap, I use this stuff all the time to cover up raw wire soldering and to water proof butt connectors
-
Mini fuse taps, these come in handy if you want to piggy back off existing HOT or switched AC power from the fuse box near the driver kick panel
-
Bosch 4-pin relay, If you buy a different relays then follow the diagram on the relay, don’t assume mine are the same.
-
Astro Multi-Meter, Here’s a cheap one that I’ve been using for over 5 years now.
