My 1991 jeep alarm goes off whenever the key is turned in any of it's doors. How can I disable the entire alarm system? Thanks

Normally you can't, it is there to stop exactly what you are trying to do. You can't disable it or bypass it, you have to fix the problem, not find a way around it. The anti-theft system is very complex and programmed into both the Body Control Module, the Engine Control Module and various sensors. It is better to go to an auto electrician, or an alarm / radio installer to fix the issue, which is a lot cheaper than the dealership.

Having said all that, they is a simple fix to disable it in this link.

https://www.google.com/search?q=2012+Jeep+Grand+Cherokee%2C+alarm+module

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for now or forever, (the latter is hacking) the former is in the book.
so the alarm only,, the car doesnt have and immoblizer.
no fobs.
just a metal key , right?>
the operators guide coves the disablement. of just the alarm.
do you have that book>?
the free manuals site is down now....
the book shows using the key at drivers door and tail gate
to do this, if you google above , see 1million hits, on topic.

http://justgivemethedamnmanual.com/

you will loose the central locking as well , remove the central locking fuse ,un less the alarm is after market fit then just remove the alarm entirely

Inset the key into the driver door and turn to unlock position three times to disengage alarm system without remote. Do the same in lock position for setting alarm without key fob.

Use your key to turn the rear hatch key cylinder before going into your jeep. That will turn off the factory security system.

Take the dash and glove box off. Under where the glove box is there are two boxes, unplug the one farthest to the left. This completley disables the security alarm.

alarm remotes not disarming system look in manule for instructions on how to place alarm in valet mode
to disable alarm

Try Turn your vehicle on, while its on unhook the alarm box from behind the dash. if you attempt to do this without the vehicle on it will not work. an other solution would be to ground the purple and yellow wire on the drivers side door

you need to find out which wires go to what like the ones going into the alarm and the ones coming from the car u might have to put them back together..hopefully they are color coordinated for you good luck

I had same problem, when a door lock broke, the car thinks it has been broken into once the alarm goes off. Mine started going off randomly when this lock broke. You have to reset the alarm system, with my 1990 Acura it was reset finally by putting key in door lock and turning key back and forth 3X. In my car, it was OK to do the key in door lock cycle in the passenger side door lock, but Acura dealer told me not all Acuras will reset it via passenger side key cycling, some require driver door lock key cycling only. I was lucky since my driver side door lock was currently useless, that my car allowed it to be done by key cycle on pass. door lock. But try that and if it doesn't fix it, just call acura dealerships until someone tells you the right answer. In my situation it took 3 dealerships with 3 different answers until this was the right one for my 1990 Legend.

PS I was told you can't disable alarm since it is all integrated into the battery and starting system, but read on another post that someone disableld theirs by disconnecting the horn.