Electrical Hidden Security Ignition Switch.

There is a wire for the fuel pump conveniently plumbed through the EEC test port in the engine bay. Cut that, then connect each end through a switch of your choice, and in the Foxbody mustang, there are any number of places to hide it out of view but within reach of the driver.

Follow this tech note for the best way to wire a fuel pump kill or anti-theft switch...

On 86- 91 cars the fuel pump relay is under the driver’s seat, 92 and later cars, the fuel pump relay is under the Mass air duct on the passenger fender well.

Note that the wire colors changed in 1991, so there are two different descriptions.

86-90 model cars:
Cut the red/black wire going to the fuel pump relay. Splice a 16 or 18 gauge wire into the wire and connect it to one side of the switch. Connect the other side of the switch to the other end of the red/black wire going to the fuel pump relay. When you are done the switch should be in the middle of the spliced red/black wire that goes to and comes from the fuel pump relay. Using the control side of the circuit allows you to use light gauge wire and light duty switches. There is less than 1 amp going through the circuit, so you don’t have to worry about voltage drop across the wiring depriving the fuel pump of electrical power.
See http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model wiring diagrams.


91-93 model cars:
Cut the Lt Blue/Orange wire going to the fuel pump relay. Splice a 16 or 18 gauge wire into the wire and connect it to one side of the switch. Connect the other side of the switch to the other end of the Lt Blue/Orange wire going to the fuel pump relay. When you are done the switch should be in the middle of the spliced Lt Blue/Orange wire that goes to and comes from the fuel pump relay. Using the control side of the circuit allows you to use light gauge wire and light duty switches. There is less than 1 amp going through the circuit, so you don’t have to worry about voltage drop across the wiring depriving the fuel pump of electrical power.
See http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model wiring diagrams.

Slo5Oh89 said:

Ideas?!?!?!

In advance thanks. Also if you could describe where and what color wires to add the toggle switch to.

Click to expand...

I bought an 88 Sable wagon from a dealer used and no one told us (or knew) about the ignition disable foot switch up high under the carpet. My wife unknowingly stepped on it and the starter would not spin. Panic. Turns out the dealer knew the PO and called him finding out what the deal was. I assume they interupted the little wire to the starter solenoid? Used what looked like an old headlight dimmer switch bolted to the floor. It worked and was invisible. I left it there and was problem free for years.