avistart 4500 in 1999 ford f150 trouble

I am hoping that someone can help me figure out this problem. I just purchased a 1999 Forf F150 and it has an Avistart 4500 installed (remote starter and remote door locks). When I brought it home, I messed around with the remote starter and it didn't work so I downloaded the owners manual and the install manual and read through them to find that the Valet mode was on and that is why the lights blinked when I hit the start button. So, I turned the valet mode off and locks work, but, when I hit the start button, the lights blink twice and the horn blares constantly until I press the start button again. The starter does not engage. Does anyone have an idea about what causes this? Marc

Usually somewhere in the manual it will have a diagnostics page...Look and see what it says about 2 flashes...It probably needs the tach re-learned...Or switched back to tachless and re-learn...Just a thought...!M.E.C.P & First-Class

Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

It appears that the flashes are normal for the starting procedure, this is from the manual; To Remote Start the Engine: 1. Press the remote control START button for 1-2 seconds, 10-15 minutes before you enter the vehicle (this will allow the climate control time to heat or cool the vehicle.) The parking lights will flash 2 times, the engine will start and the parking lights will remain on as a visual indication that the engine is runningMarc

Does the vehicle have factory alarm.  Try this.  close the drivers door and unlock it with the key in the door cylinder.  try remote starting after doing that and see if the alarm still sounds and the vehicle starts.  Ford products will arm the factory alarm if you hit the lock switch with the drivers door open.  A theft light on the dash will go solid after doing this and begin to flash after the door is closed.  They may have not hooked up a disarm wire and that is why the alarm is being triggered.  This was the only way to arm that alarm and often shady installers did not even realize it was there and would neglect to hook up the disarm wire.  Maybe you inadvertently armed the alarm, it could also be done by you locking the doors with the avital remote while a door was opened.  The avital system should not sound the horn when remote starting and it has to be vehicle related.  The two flash confirmation is normal for remote start initiation.  By the way does the ignition turn on after the two light flashes ?

I just remembered the older avitals would lock the doors on remote start initiation.  If remote starting was done while the door was opened it would have armed the factory alarm.  sit in the vehicle with the door closed and remote start.  See if that fixes your problem.  Keep your foot neat the brake in case it overuns so you can cancel remote start.