Every time I open doors, the horn blows and lights flash I never got a remote thing last about 3 mins then go off happens if the car is running and you open doors or not

To arm content theft alarm.
1. Open the door.
2. Lock the door with the power door lock switch or
the remote keyless entry transmitter. The
SECURITY light should flash.
3. Close all doors. The SECURITY light should go off
after approximately 30 seconds. The alarm is not
armed until the SECURITY light goes off.

If a locked door is opened without the key or the remote keyless entry transmitter, the alarm will go off. The headlamps and parking lamps will flash for two minutes, and the horn will sound for 30 seconds, then will turn off to save the battery power.

Just a guess but your remote may be shorting out on the panic button. Try taking the battery out of the remote and just using the key to open the doors for a day or two and see if it still does it. If not, replace the remote. Another more likely possibility with this particular vehicle could be the door switches. The door switches on my Windstar would cause the dome light to stay on all the time when the contacts get corroded. If you van is locked with the alarm armed it could be the door switch causing the alarm to think someone has opened a door even when they haven't. (You can remove and clean or just replace all of the door switches or track down the particular suspected door switch. Mine was always the sliding door..clean the contacts with scotch brite or steel wool and coat with very thin battery terminal grease.)

try disconnecting the battery neg lead and the pos lead then join them together for 5 mins then reconnect the battery and see what happens ,it might just reset the fault for you .

IMPREZA: 2005, 2006, 2007 and
FORESTER: 2005, 2006, 2007, 2008
Check for Immobilizer key on Forester XT models only.
information is always subject to change and correction
new remote for 2005 Imprezas.
This is not the same remote as the 05 Legacy/Outback remote which also has truck/gate release on the front and a red panic button on the back.
Lock: press Lock button for 2 seconds or so to lock car, and arm optional security system. The car with chirp once and turn signals flash for locked, 5 short chirps and signal flashes if any door is not fully closed. The dome light goes on for 15 seconds and ignition key ring (if present) will light for 30 seconds when unlocked.
Unlock: press unlock one time for driver's door, press again within 5 seconds to unlock all doors inkling rear gate (wagon). The system does not open the trunk.
Panic mode: press and hold lock button for approx. 3-4 seconds to activate Panic mode. I panic model the horn honks and turn signals flash until either the lock or unlock button is pushed again.
Finder mode: Press lock button 3 times within 5 seconds to activate Vehicle Finder mode. The horn will honk once and the turn signals will flash 3 times
Distance: works within approx. 30 feet depending on battery strength, nearby concrete walls and etc.
Audible Chirp On-Off: the system will chirp when locked or unlocked. To turn OFF the chirps, unlock the door and then push both lock and unlock buttons at the exact same time for 2+ seconds. There will be 2 chirps indicating the the audible is off. To turn the chirp back on, repeat the process and the system will chirp one time when it is back on.
Battery: as the battery ages it will only work as you get closer to the car. When a battery is replaced, the transmitter must be re-synchronized with the Keyless control unit. To synchronize, press the lock or unlock button 6 times.
Programming: 4 codes may be programmed.
Sit in driver's seat and unlock all doors. Open and close the driver's door
Turn the ignition key from LOCK to ON position 10 times within 15 seconds. Be sure to stop at both lock and on. The horn will HONK once to indicate transmitter programming mode is activated. Leave key in LOCK position and don't remove it from ignition.
You now have 45 seconds to complete the programming as below.
Open and close driver's door again.
Push either lock or unlock button on the remote you want to program. The horn will honk 2 times when successful.
To continue and program other remotes at the same time: open and close the driver's door and push lock or unlock on the remote. The driver's door must be opened and closed between each remote you want to program.
Done programming? remove the key from the ignition and the horn will honk 3 times.
DELETE old codes? Reprogram 4 times, it will overwrite old codes.
Alarm Security System: optional on all models. When locked there is one chirp (can be turned off, see above), the turn signals will flash and the red 'security' light will start to flash once every 2 seconds except for STi which flashes twice every 2 seconds.
There will be 5 chirps if a door, hood, and trunk or gate is not fully closed
You can also arm the system by using the power lock button on the driver or passenger door as you get out of the car and then closing the door behind you.
Disarm the system: push unlock for 2 seconds
Lost remote, alarm activated? When you can't use a remote to turn off the system: open the door with a key or try to start the car and the horn will start to honk. Turn the key on-off 3 times within 5 seconds and the alarm will go off and you can start the car. It's simple!
VALET mode: To set valet mode or just to disable the security alarm system: 1. unlock all doors 2. physically open the driver's door 3. hold the UNLOCK button on remote for 2+ seconds. The red 'security' light will then flash 2 times a second until the car is turned on.
System has been Tripped (except for STi): if you unlock the door with the remote and it chirps the signal light flash 4 times, the system has been triggered;
Identification mode: To find out what happened and why the system was triggered:
Open and drivers door, leave it open. Turn ignition key from LOCK to ON 2 times and then leave in LOCK position.
Tripped code: 1 security light flash: a door has been opened, 3 flashes when the impact sensor was triggered, 4 flashes when the ignition was messed with or battery disconnected

you have to have a remote if you want to sort the problem for good.

I think your horn relay is making contact from behind your horn buttons on your steering wheel. Usually as time creeps up the insulation that is placed on the positive lead for the horn gets worn out from constant horn action. If it is worn down the horn is touching a ground and completing the circuit and thus making the horn sound. I would start with that first before getting more technical. Let me know. Gabe

. Seems like the system is not being diarmed. If it wont disarm with remote or by the door klock key, try this. Don't use the power door lock button to lock the car. Lock it MANUALLY till its repaired

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