Had a chance to clear my head - and wanted you to do the following....
Open the door (keep it open)
Put the key in the ignition and turn to run.
Press the LED 3x
You should hear 1 chirp.... and the led will blink once...pause...once...pause etc.
(This means you are in programming bank 1& Now we need to see if the alarm recognizes the remote.)
Within 15 seconds - Press and HOLD the LOCK button on the remote until the siren warbles.
This means the Lock function is enabled on that remote. (continue)
Now press the LED 2x
Siren should chirp 2x and LED blink 2...pause...2...pause etc.
Press & HOLD the UNLOCK button on the remote until the siren warbles.
Now UNLOCK has been programmed.
Turn the key to OFF, and the siren will warble.
Now you can at least unlock/lock without the alarm sounding.
I am not with my Audiovox programming list at the moment... so I'm not sure what channel 3 and 4 are (and remote start)... but if you've gotten this far - the brain is not failed. Reply with the model # XXXXX the transmitter - and perhaps I can find documentation online.
If you cannot get into programming mode at all - it would appear the brain has, indeed, developed an issue that needs to be looked at by the installer.
Let me know what you find out.
Here is a video that may explain it better. It's not the exact model - but all Audiovox/Pursuit etc. use the same basic technique.LINK