The buzzer works when the door is open and the key is in the ignition. The door open indicator light and buzzer will be on with the door open and
the ignition switch in the Accessory position.
The following will happen when the ignition switch is turned to the start position:
The buzzer and dash light will work if you do not have your seat belt fastened.
With the door closed, the buzzer will work for about 7 seconds if the belt is not fastened, the light will stay on.
With the door closed and the belt fastened, the buzzer will be off and the light will stay on for 7 seconds.
If the door is not closed and the belt is fastened, the door light will stay on, the buzzer will stay on and the seat belt light will turn off in 7 seconds.
The Buzzer is located on the left side of the steering column, under the kneepad. It's mounted on a plate that also has the wiper logic box on it.
The biggest problem in getting the buzzer to work properly is the electrical connectors under the dash. After you have the door switches connected properly, check your schematic, you will then need to pull the electrical connectors off, clean and straighten the contact strips. You might have to do this to the connectors that attach to the instrument cluster. Also, the ignition switch will hang up, there is a spring loaded switch for the buzzer circuit inside the ignition switch. You can spray some contact cleaner in
the switch, then lubricate it lightly with some spray lube. Be careful of overspray, you do not want to harm any surface inside the car.