How do you remove or disable the alarm system from a 1996 to 200X Ford vehicle eg. Econoline Mustang Taurus etc?

Answer 1

Before you start hacking at the system, let's understand a bit about how it works.

Your Ford vehicle may have two different and independent security systems. The systems will cause different "faults" and you need to understand which system has the issue before you attempt a resolution.

The first system is the Ford Passive Anti Theft System or PATS. The PATS system was introduced in 1996 on some luxury models and has become a standard since. PATS uses special ignition keys with an RFID transponder embedded in the bow (head) of the key. The ignition switch has an embedded RFID reader that communicates with the PCM (the computer) and, if the ID number in the key has been stored in the computer, the computer will allow the vehicle to run. If the ID number is not stored in the computer, the computer will post and OBD Error code (1260) and will keep the engine from running. This can be disabled by loading a "tune" file that instructs the PCM to ignore the error (the 1260 is still there - just ignored).

IMPORTANT NOTES:

• The PATS does NOT inhibit the starter - the car will crank - but not run.
• If you have 2 RFID keys - you can program more - Follow the instructions in the owners manual.
• If you only have 1 RFID key, you will need to go a good locksmith / dealer.
• If you change the computer - your RFID keys won't be loaded in it.
• The PATS is generally not At Fault when the car won't crank - read on.

The second system often a dealer installed option called the Ford Vehicle Security System - System 3 or System 4. This system disables the vehicle starter. The system 4 comes standard with an Impact Sensor and Siren - they are options on the System 3. The "brains" of the system is a black box with three connectors as follow:

• 2 pin connector with 2 Red wires - these go to an internal relay that opens and closes the circuit to actuate the starter relay. The installer physically cuts the wire from the ignition switch and splices this into the circuit.
• 16 pin connector with lots of wires. There is a wiring diagram on a sticker on the back of the alarm module but, in a nutshell - 3 wires for the valet push button and LED, 2 wires to the "Emergency Override", a switched B+ line and a constant B+ line (both fused), a ground, a hood switch line, 2 lines to parking lights, 2 for the siren and 3 for door/key lock / functions.
• 4 pin connector the the Impact Sensor

This system can be disabled by connecting the two red wires. The system can also be completely removed without impacting the PATS.

IMPORTANT NOTES:

• This system has no impact on the Remote Keyless Entry - operates independently (your remote buttons will still work!).
• This system will prevent the car from cranking if it is faulted.
• This system is the car alarm - remove it and you have no alarm.
• This is the system that tends to get out of sync when you change batteries or jump start the vehicle. It can be re-initialized:

1. Turn off the vehicle
2. Disconnect the battery for 2 minutes
3. Switch the key to the "RUN" position
4. Reconnect the battery
5. Switch the key to the "OFF" position
6. Press the "Lock" switch on the drivers side door

How I learned this:

My 2000 Mustang refused to start for my wife. The alarm had been "quirky" before but pressing the "Lock" then hitting "Unlock" twice would usually allow it to start. Sometimes we had to press the "Emergency" button while trying to crank - but things worked OK most of the if you fooled with them. After I fooled with it for about 15 minutes, it started but, when I switched it off to show her it was fine, it refused to crank again. I read all the forums I could find and the answer was always - "The vehicle needs to be towed to the Ford Dealer for repair." It was time to resolve the issue.

I climbed under the dash and found that the problem was probably not so much the system as the installation. The installer had stripped back wires, wrapped the ends of the connections around the conductor and taped over the "connections" - no crimps, no solder, no quality. In short, this installation was a failure waiting to happen from day one.

I completely removed the inferior work and, with solder, heat shrink and an entire afternoon, returned the harnesses to "stock". The car starts every time, the remote and PATS still work and I don't have to worry about stranding the family because of a bad connection.

Q: How do I know if I have PATS?

A: Check your key - does it have a thick top (bow)? If so, it might be an RFID key. Our neighborhood ACE hardware makes keys; they have a tool that will test for an RFID key - and they test it for free.

Q: Where do I get a "tune" to disable the PATS?

A: Check the internet - WARNING: In some states, cars with custom "tunes" won't pass vehicle inspections - especially emissions test.

Q: What else might keep my vehicle from starting?

A: Make sure the car is in PARK or Neutral. The Neutral Safety Switch is a safety interlock to keep the vehicle from cranking when in gear.

Remember, if it cranks but won't run, it may be PATS; if it won't crank (starter solenoid does not click) it might be the System 3 / System 4.

Good luck. I hope this helps.