1999 ford mustang wont start anti theft blinking

If it is blinking rapidly then your computer is not receiving the signal from your key chip. If you have a tilt steering wheel, try moving it up or down with key in the ignition until the red light stops flashing. Your car should start. The problem is most likely a loose wire connector on receiver. You can fix it yourself by removing the steering column cover. The receiver fits over the ignition cylinder and has 4 wires on it. The connector can probably be fixed by pushing the wires in firmly. Check all 4 wires to make sure none are loose and secure them in place by whatever means necessary. The wires are about a foot long with a white plastic connector on the end. The wires are very small so if you think you will have a problem securing them, you can purchase a new receiver at a ford dealer for about 50 bucks. The information I just gave you cost me just over 1100.00 dollars almost exactly a year ago. That is what it cost me by the time mine was fixed when it left me stranded and the the tow trucks and mechanics were done trying to figure it out while replacing the fuel pump, pump filter and computer over a period of 2 weeks. I figured out where the problem was when I adjusted the steering wheel after all the mechanics were stumped. Make sure you check this before you talk to a mechanic. Wish I did.

I should have mentioned that the 50 dollar price tag for the receiver is Canadian funds at a Canadian Ford dealer. My car is a 99 lincoln town car but the part should be the same. The part is F8SB-15607-AC made by SIEMENS.

Just found my invoice for the new part and the proper name is Transceiver and the part number on the invoice is YW1Z 15607 and the actual price is $60.83 before tax. The part number I quoted previously was on the old part. I searched online pricing and my cost would have been closer to 50 bucks to purchase online. Again this is all Canadian prices.