Originally Posted by
Boat Tug
If your alarm system is the same as pictured above, the procedure is:
<hr style="color: rgb(255, 255, 255); background-color: rgb(255, 255, 255);" size="1"> Disconnect the battery. Wait 2 minutes for the module to lose all traces of voltage. Turn the ignition key to the RUN position. Reconnect the battery. Shut the key OFF and press LOCK on the drivers door switch. It's called reinitializing the alarm.
I just experienced the same exact issue with my 2000 Expedition where after changing my battery the alarm system prevented me from turning on my car. Once I followed the instructions for re-initializing the alarm quoted above everything went back to normal.
Thank you so very much for posting this information it really helped!
