1998 Ford Expedition theft light is blinking rapidly and will not start

SOURCE: 1998 ford expedition blinking overdrive light

This blinking light indicates a problem. You will have to have it scanned for trouble codes to find out
what it is.

SOURCE: 1998 ford expedition wont start. theft like is

If you are reseting a factory alarm...lock and unlock the drivers door with the key. If you don't know the code look under the dash driver side in left corner there should be a black cover with a sticker with a code on it 6 numbers that is the factory code.

SOURCE: 1998 ford expedition that won't start. it cranks,

The theft light blinking indicates a PATS (perimeter anti-theft concern.It means that the computer has not recieved a signal from your key when trying to start the vehicle. A few things could be wrong.
1...The key you are using to start the vehicle is not programmed to the vehicle or broken internally. So try a different key(one that you know is programmed to the vehicle) if you have more than 1. If the theft light goes on and flashes when you try to start the vehicle, you must wait about 5 minutes before trying the second key because the computer goes into antiscan or theft mode and wont let any keys start the vehicle.
2... There is a small transciever ring located arount the key cylinder which recieves the key signal. The wiring for the tranciever runs down the steering column into the dashboard wiring. Sometimes these wires break. If you have a tilt steering wheel, move it all the way down and try to start, then try moving it all the way up and try to start. Keep in mind the antiscan that I mentioned in #1. If this works then you need to check the wiring at the base of the steering column. A white connector with 4 wires. Pull on each wire to see if any are broken.
3... Check fuse #30 on interior fuse panel. If it is blown then you will have to trace down the cause of the short. The ignition coils are on this fuse also so one could be shorted. Disconnect all ignition coils(you may have 8 located on each plug if 5.4l engine or 2 located on l+r front of engine if 4.6l engine) and see if the short is gone. If the short is still present disconnect the radio noise supression capacitors( small black box approx 1" x 1" square with a single wire coming out) that are located on the left and right front of the engine. Pay close attention to all the wiring around the coils, look for any areas that may have rubbed thru and shorted.
These are things that I would look for first and are the most likely causes. This should get you started in the right direction. Be patient and post your findings if you fix it or not.
Good luck

SOURCE: i have an 1998 ford

Follow this link, just copy and paste.
http://www.ehow.com/how_5844411_reset-theft-protection-ford-expedition.html

paulmacintyre

• 3218 Answers
• Posted on Oct 18, 2015

SOURCE: 2001 ford ranger wont start theft light blinking rapidly

try locking/unlocking doors with key fob. Also try locking unlocking drivers door with key to see if system resets