How do you disarm the built in alarm system on a 1995 Buick Riviera?

It is easier to just fix it the right way. But to answer your question, this is how you would by pass the security key. 1st you have to determine the Ohm reading for the security system. For this you have to either have the correct security key that goes to the car, or you have to have a special machine to decode the system. If you have the key, then you will notice that it has a built in "resistor" chip in the key. Use an ohm meter to determine the resistance of the key chip. Then go to radio shack and purchase a resistor with the same ohm rating. Then you will need to locate the wires under the dash that go to the key lock cylinder-NOT THE AIR BAG. Their are 2-wires that are orange or yellow-about the same gauge as a telephone jack wire. Cut the wires and solder each end of the resistor to each wire. You have now bypassed the security key, and key lock cylinder.

As you can see, it would be a lot simpler to just fix the original problem, which is usually just a broken wire on the keylock cylinder in the steering column. The key lock cylinder MUST be replaced. If you try to just solder the tiny little wire it will work for a few weeks, but will break again right next to the repair.