Something killing the battery in steering column 2003 Buick Rendezvous

How do you know it's in the steering column ???? You have no idea of the complexity of the electronic's in that vehicle . Why don't you stop triyng to play auto technician. ???? Do you know how the charging syatem works on that vehicle ,or the serial data buss ( or communication network) ,what the computers (modules ) talk to each other on ???? The charging system on that vehicle is computer controlled . Do not blame the regulator because you don't have a clue how the system works . Is the check engine light on ??? You also have no idea how the BCM - body control module comes into play in the electronics on that vehicle . I have thrity years as a GM technician . An you have no clue .What happens when you turn the key to start .do you ??
Circuit Description
Moving the ignition switch to the START position sends a 12 V signal to the PCM Ignition Crank Sense. The PCM then grounds the control circuit, which travels through the Park Neutral Position switch, of the CRANK relay . When the CRANK relay is energized it allows voltage to the starter solenoid S terminal.

How about BCM control ??

BCM Functions
The body control module (BCM) is capable of accomplishing multiple body control functions. Components directly connected to the BCM are controlled by the BCM outputs. The BCM can control its outputs based on input information it obtains from sensors and switches that are directly connected to the BCM, or by receiving information from other vehicle systems connected to the class 2 serial data link. The BCM evaluates this information and controls certain body systems by commanding an output on or off.
The BCM is also capable of commanding other vehicle systems to control functions that are not directly wired to and/or controlled by the BCM. The BCM accomplishes this task by sending specific messages on the class 2 serial data link. The vehicle system capable of performing such function will respond to the BCM message.
The BCM controls/monitors the following functions:
• Audible warnings
• Indicators control
• Interior lighting
• Exterior lighting
• Power/automatic door locks
• Keyless entry
• Content theft deterrent
• Personalization
• Serial Power Modes
• Electrical Power Management


Do yourself a favor an take it to a qualified repair shop ,an quit trying to play automotive BCM Functions
The body control module (BCM) is capable of accomplishing multiple body control functions. Components directly connected to the BCM are controlled by the BCM outputs. The BCM can control its outputs based on input information it obtains from sensors and switches that are directly connected to the BCM, or by receiving information from other vehicle systems connected to the class 2 serial data link. The BCM evaluates this information and controls certain body systems by commanding an output on or off.
The BCM is also capable of commanding other vehicle systems to control functions that are not directly wired to and/or controlled by the BCM. The BCM accomplishes this task by sending specific messages on the class 2 serial data link. The vehicle system capable of performing such function will respond to the BCM message.
The BCM controls/monitors the following functions:
• Audible warnings
• Indicators control
• Interior lighting
• Exterior lighting
• Power/automatic door locks
• Keyless entry
• Content theft deterrent
• Personalization
• Serial Power Modes
• Electrical Power Management


Circuit Description
The generator provides voltage to operate the vehicle's electrical system and to charge its battery. A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the battery terminal.
When the engine is running, the generator turn- on signal is sent to the generator from the engine control module (ECM), turning on the regulator. The generator's voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator F terminal is connected internally to the voltage regulator and externally to the ECM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the ECM that a problem exists. The ECM monitors the generator field duty cycle signal circuit. The system voltage sense circuit receives B+ voltage at the body control module (BCM).This voltage is used by the regulator as the reference for system voltage control.
When the ignition switch is turned to RUN, the charge indicator turns on for a few seconds (bulb check), then turns off. The ECM commands the bulb of the charge indicator on by sending a class 2 serial data line message to the instrument panel cluster (IPC) when the ECM detects a charging system problem.


You have no idea about this stuff . so , stop

The dieing is almost certainly caused by a bad regulator in the alternator (new or not) or the wiring is not connected correctly. As far as the noise is concerned, you will need to describe it better (e.g. clicking?) and confirm where in the column it is coming from (e.g. near the wheel or close to or under the dash?).