Why is there loud warning chimes randomly sounding from my 2006 Buick Terraza, with no steady pattern, frequency, and happens regardless of gear, movement or even if engine is off or on.

your best bet , take it to a qualified repair shop. Have it checked for DTC'S - diagnostic trouble code's

Audible Warnings Description and Operation
The audible warnings alert the driver of a system concern or a critical vehicle condition. The instrument panel cluster (IPC) generates audible warnings through an internal acoustic speaker. The IPC receives audible warning requests via the serial data circuit. If the IPC receives multiple audible warning requests, the warning with the highest priority sounds first. The following lists the audible warning priority and the pulse rate:
Fast rate chime (200 pulses per minute)
Medium rate chime (150 pulses per minute)
Slow rate chime (50 pulses per minute)
Single chime
Door Ajar Warning
The IPC activates the door ajar audible warning as requested by the body control module (BCM). The BCM sends a serial data message to the IPC indicating the chime frequency and duration. The door ajar warning sounds and the appropriate DOOR AJAR indicator illuminates in the driver information center (DIC) when the following occurs:
• The body control module (BCM) determines that a door, driver door, passenger door. The IPC receives a serial data message from the BCM indicating the door ajar status.
• The vehicle is not in park. The IPC receives a serial data message from the BCM indicating the gear position.
• The vehicle speed is greater than 8.05 km/h (5 MPH). The IPC uses the vehicle speed information from the ECM to calculate the vehicle speed.
Fasten Safety Belt Warning
The IPC activates the fasten safety belt audible warning as requested by the BCM. The BCM sends a serial data message to the IPC indicating the chime frequency and duration. The fasten safety belt warning sounds and the fasten safety belt indicator illuminates when the following occurs:
• The ignition switch transitions to ON.
• The inflatable restraint sensing and diagnostic module (SDM) detects that the driver's seat belt is not buckled. The IPC receives a serial data message from the SDM indicating the drivers seat belt status.
If the seat belt is buckled when the ignition is turned ON, the chime will not sound. If the seat belt is buckled while the chime is sounding, the chime will stop. If the seat belt is unbuckled after the initial transition to ON, the chime will not sound.
Key-In-Ignition Warning
The IPC activates the key-in-ignition audible warning as requested by the BCM. The BCM sends a serial data message to the IPC indicating the chime frequency and duration. The key-in-ignition warning sounds when the following occurs:
• The ignition switch is OFF.
• The body control module (BCM) determines that the driver's door is open. The IPC receives a serial data message from the BCM indicating the door ajar status.
• The BCM determines that the key-in-ignition switch is closed and the signal circuit is low. The IPC receives a serial data message from the BCM indicating the key-in-ignition status.
Lights On Warning
The IPC activates the lights on warning as requested by the body control module (BCM). The BCM sends a serial data message to the IPC indicating the chime frequency and duration. The lights on warning sounds when the following occurs:
• The ignition is OFF.
• The BCM determines that the drivers door is open and the signal circuit is low.
• The BCM determines that the headlamp switch is in the park or head position.
Park Brake Warning
The IPC activates the park brake audible warning as requested by the BCM. The BCM sends a serial data message to the IPC indicating the chime frequency and duration.
• The body control module (BCM) determines that the park brake is applied.
• The vehicle is not in park. The IPC receives a serial data message from the engine control module (ECM) indicating the gear position.
• The vehicle speed is greater than 8.05 km/h (5 mph). The IPC uses the vehicle speed signal information from the engine control module (ECM) in order to calculate the vehicle speed.
Additional Warnings
The following warnings have an associated instrument panel cluster (IPC) indicator or driver information center (DIC) message:
• Check Oil Level
The IPC activates the audible warning as requested by the BCM. The BCM sends a serial data message to the chime producer indicating the chime frequency and duration.
• Low Fuel
The IPC activates the audible warning as requested by the BCM. The BCM sends a serial data message to the chime producer indicating the chime frequency and duration.
• Oil Pressure Low Stop Engine
The IPC activates the audible warning as requested by the BCM. The BCM sends a serial data message to the chime producer indicating the chime frequency and duration.
• Reduced Engine Power
The IPC activates the audible warning as requested by the BCM. The BCM sends a serial data message to the chime producer indicating the chime frequency and duration.
• Trans Hot Idle Engine
The IPC activates the audible warning as requested by the BCM. The BCM sends a serial data message to the chime producer indicating the chime frequency and duration.
• Turn Signal On
The IPC activates the audible warning as requested by the BCM. The BCM sends a serial data message to the chime producer indicating the chime frequency and duration

Check just after it die to see if you still have good spark at plugs.

how can I get the door chime to stop working when I put my 2007 terraza indrive it gose off and wont stop the only thing I did was disconnect the negative batter cable to do some work and when I put it back on this is when it started. can someone please help thank you

Look up under dash and use a length of hose with one end in your ear to listen to find where the sound is coming from. You should be able to just unplug the chime unit.

be sure all doors are closed, put the key in passengers door and unlock and lock it with the key, do the same to drivers door, that should stop the chime.

The audible warnings alert the driver of a system concern or a critical vehicle condition. The radio generates the audible warnings through the left front speaker. The radio receives audible warning requests via the class 2 serial data line from the IPC or body control module (BCM). If the radio receives multiple audible warning requests, the warning with the highest priority sounds first. The following lists the audible warning priority and the pulse rate:
Fast rate chime--200 pulses per minute
Medium rate chime--150 pulses per minute
Slow rate chime--50 pulses per minute
Single chime

Is the sound heard different from typical Audible Warnings ?

Fasten Safety Belt Warning
The radio activates the fasten safety belt audible warning as requested by the IPC. The IPC sends a class 2 message to the radio indicating the chime frequency, slow rate and duration (5 pulses). The fasten safety belt warning sounds and the fasten safety belt indicator illuminates when the following occurs:
• The ignition switch transitions to ON.
• The inflatable restraint sensing and diagnostic module (SDM) detects that the driver's seat belt is not buckled, signal is low. The IPC receives a class 2 message from the SDM indicating the driver's seat belt status.
If the seat belt is buckled when the ignition is turned on, the chime does not sound. If the seat belt is buckled while the chime is sounding, the chime stops. If the seat belt is unbuckled after the initial transition to ON, the chime does not sound.
Headlamps On Warning
The radio activates the headlamps on warning as requested by the body control module (BCM). The BCM sends a class 2 message to the radio indicating the chime frequency, fast rate and duration, continuous. The headlamps on warning sounds when the following occurs:
• The ignition is OFF.
• The BCM determines that the driver's door is open, signal is low.
• The BCM determines that the headlamp switch is in the park or head position.
Key-In-Ignition Warning
The radio activates the key-in-ignition audible warning as requested by the BCM. The BCM sends a class 2 message to the radio indicating the chime frequency, medium rate and duration, continuous. The key-in-ignition warning sounds when the following occurs:
• The ignition switch is OFF.
• The body control module (BCM) determines that the driver's door is open, signal is low.
• The BCM determines that the key-in-ignition switch is closed, signal is low.
Turn Signal Reminder
The radio activates the turn signal warning as requested by the IPC. The IPC sends a class 2 message to the radio indicating the chime frequency, medium rate and duration, continuous. The turn signal warning sounds when the following occurs:
• The ignition switch is in the RUN position.
• The turn signal switch is in either turn position, sensing, within 1 second, an open to B+ transition in the turn signal control circuit, left or right turn.
• The vehicle has traveled a distance of 1.2 km (¾ mi) by counting pulses on the vehicle speed input circuit.
The IPC turns OFF the turn signal reminder when either the ignition switch is turned to the OFF position, or the turn signal switch returns to the OFF position, sensing, within 1 second, no transitions from open to B+ in either of the turn signal control circuits, left turn or right turn.
Additional Chimes
The following chimes will turn ON when an associated indicator/message turns ON in the IPC/DIC:
• ABS indicator
• AWD Disable indicator
• Battery/Charge indicator
• Brake indicator
• Change Engine Oil indicator
• Door Ajar indicator
• Hot Coolant Temp indicator
• Low Brake Fluid indicator
• Low Fuel indicator
• Low Oil Level indicator
• Low Oil Pressure indicator
• Low Tire Pressure indicator/reset
• Low Washer Fluid indicator
• MIL (Service Engine Soon) indicator
• Oil Life Reset
• Park Lamp Out indicator
• Rear Hatch Ajar indicator
• Service Traction System indicator
• Service Vehicle Soon indicator
• TRAC OFF indicator
For a description of an indicator refer to Indicator/Warning Message Description and Operation .
For diagnosis of an indicator refer to Symptoms - Instrument Panel, Gages and Console .

Did the Mechanic check for DTC'S - diagnostic trouble codes in the BCM or insturment cluster ? Did you try a Buick dealer ?

maybe low on coolant, check water to coolant ratio.

My passenger side door would not close. The mechanic reprogrammed it with the instructions in the handbook. So far it is working OK after one month. Good luck

Well I would post a solution but I feel like "fixya" should pay me for telling them. It kind of bothered me that I was going to have to pay for assistance. Usually someone will look at your vehicle for free just to figure out the problem.