2001 Ford Taurus anti theft system

Changed my battery and now the anti theft light on the dash flashes and the car won't start. All I get is the MCL clicking noise from the starter. I only have 1 key and the fob don't work. The dealership wants 152.00 to reprogram the key. It worked fine before the battery died. I can't find the reset button under the dash themi keep reading about. Please tell me where it actually located. And today someone said there is actually a red light under the dash. Is this true? Cars been down for 4 days now so if you could help I would be very grateful. Thank you.

Their are plenty of solution's on the web Here are a few to try.

Reset the computer. You do this by inserting key and turn to on position and disconnecting the negative side of the battery for a minute or so, then reconnect it with key still on and make sure the connections are tight on the positive and the negative side. Try starting the car. If that doesn't work, try resetting the factory alarm which has a kill switch built in. Open driver's door, insert key, turn to on, leave like that for exactly 10 minutes, after which turn key off. close driver's door and then try to start the car normally, this resets the anti theft device.

Also to reset the alarm press and hold last two door entry buttons - together - for about ten seconds. Then, unlock door with the key, get in, close door, and car would start.

Do not ever power-up or de-power the ECM with the IGN on. Ie by "disconnecting the battery with the key on". You turn the key on AFTER the battery is disconnected. Even better is turn the headlights on.

To the OP: Be careful following advise on the internet. Sometimes it's worth what the guy charges for it. Or in this case even less because a new ECM is not inexpensive if you damage it following his "advise".

Manufacture certified Technicians do it all the time but "ONLY WITH THE NEGATIVE BATTERY CONNECTION!

NEVER DO IT WITH THE POSITIVE BATTERY CONNECTION AS DAMAGE TO ECM CAN OCCUR.

Their were TSB"s for Early GM VATS (Passkey 1) instructing to exactly that Disconnect Negative battery cable with "Key ON" wait 1 minute then reconnect to reset VATS.

Surely disconnecting EITHER battery terminal with the ignition on will prove expensive.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

It does not matter if it is the positive or negative terminal, it takes both to complete the circuit. Unhooking 1 over the other makes no difference.

Either one will break the circuit, but it's safer to disconnect the negative terminal, since it's a negative ground vehicle. If you accidentally touch your wrench or ratchet to ground while loosening the terminal, you get no spark. If you do the same with the positive terminal, you get a big spark, and could possibly ignite the explosive fumes produced by the battery.

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My ex once told me I have a perfect face for radio.